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Simultaneous Quaternary Radiations of Three Damselfly Clades across the Holarctic
Abstract
If climate change during the Quaternary shaped the macroevolutionary dynamics of a taxon, we expect to see three features in its history: elevated speciation or extinction rates should date to this time, more northerly distributed clades should show greater discontinuities in these rates, and similar signatures of those effects should be evident in the phylogenetic and phylodemographic histories of multiple clades. In accordance with the role of glacial cycles, speciation rates increased in the Holarctic Enallagma damselflies during the Quaternary, with a 4.25x greater increase in a more northerly distributed clade as compared with a more southern clade. Finer-scale phylogenetic analyses of three radiating clades within the northern clade show similar, complex recent histories over the past 250,000 years to produce 17 Nearctic and four Palearctic extant species. All three are marked by nearly synchronous deep splits that date to approximately 250,000 years ago, resulting in speciation in two. This was soon followed by significant demographic expansions in at least two of the three clades. In two, these expansions seem to have preceded the radiations that have given rise to most of the current biodiversity. Each also produced species at the periphery of the clade's range. In spite of clear genetic support for reproductive isolation among almost all species, mtDNA signals of past asymmetric hybridization between species in different clades also suggest a role for the evolution of mate choice in generating reproductive isolation as species recolonized the landscape following deglaciation. These analyses suggest that recent climate fluctuations resulted in radiations driven by similar combinations of speciation processes acting in different lineages.
... The proper taxonomic rank of rotundatum is another issue. Its junior synonym, E. risi, was considered a bona fide species by several authors Turgeon et al. 2005;Bernard & Kosterin 2010;Callahan & McPeek 2016;Boudot et al. 2021), while others regarded it as the subspecies E. cyathigerum risi (Samraoui et al. 2002;Kosterin & Zaika 2010, 2011Schröter et al. 2015;Kosterin & Ahmadi 2018;Schneider et al. 2018). Authors from both parties used molecular phylogeny in their attempts to clarify the issue (Samraoui et al. 2002;Turgeon et al. 2005;Callahan & McPeek 2016). ...
... Its junior synonym, E. risi, was considered a bona fide species by several authors Turgeon et al. 2005;Bernard & Kosterin 2010;Callahan & McPeek 2016;Boudot et al. 2021), while others regarded it as the subspecies E. cyathigerum risi (Samraoui et al. 2002;Kosterin & Zaika 2010, 2011Schröter et al. 2015;Kosterin & Ahmadi 2018;Schneider et al. 2018). Authors from both parties used molecular phylogeny in their attempts to clarify the issue (Samraoui et al. 2002;Turgeon et al. 2005;Callahan & McPeek 2016). It is crucial that in Middle Ural (Sverdlovsk Province), Altai Mts (Kosterin 2004), and Tuva (Kosterin & Zaika 2010, 2011, transition populations exist with males having both boreale-and cyathi gerum-types of the cerci, while the cyathigerum-type is represented by the subtypes with the yellow lobe either visible or concealed in dorsal view. ...
... The phylogenetic reconstruction based on AFLP analysis of nuclear DNA by Turgeon et al. (2005) showed that E. risi (the name used in this publication) was nested inside the paraphyletic E. cyathigerum [s. str.] clade. ...
Enallagma cyathigerum var. rotundatum Bartenef, 1929, Leucorrhinia circassica Bartenef, 1929, and Aeschna juncea var. atshischgho Bartenef, 1929, were described by A.N. Bartenev (= Bartenef) in three papers published in 1929 and 1930. Their type locality was the same highland lake group near Krasnaya Polyana Town in West Caucasus, Russia, presently known as the Khmelevskie Lakes. Their type series most probably no longer exist. Topotypes of the two former taxa obtained in 2008 and 2013, respectively, were examined as well as a specimen supposedly of the third taxon, collected 36 km from the type locality. Based on these specimens, E. cyathigerum rotundatum is concluded to be a valid subspecies and the senior subjective synonym of Enallagma risi Schmidt, 1961, and L. circassica to be a junior subjective synonym of Leucorrhinia dubia (Vander Linden, 1825). The status of A. juncea atshischgho remains unresolved. Re-evaluation of available knowledge of the Palaearctic Enallagma spp. suggested downgrading Enallagma deserti (Selys, 1879) to the subspecies, E. cyathigerum deserti.
... Previous work showed that multiple local variables can shape odonate community structure, including abiotic factors such as water chemistry (Correa et al. 1985, Hudson and Berrill 1986, Bendell and McNicol 1987, Pollard and Berrill 1992, Johansson and Brodin 2003, Rychła et al. 2011, Siepielski et al. 2011, biotic factors, such as fish predation (McPeek 1990) and vegetation structure (Solski and Jedrczak 1990, Toivonen and Huttunen 1995, Pietsch 1996, and stochastic processes such as dispersal and ecological drift (McCauley 2006, Siepielski et al. 2010. Moreover, the evolutionary history of particular odonate lineages has likely had a strong influence on communities located in temperate and boreal regions (McPeek and Brown 2000, Turgeon and McPeek 2002, Turgeon et al. 2005. A highly studied genus of damselflies, Enallagma, experienced a recent radiation during the last glaciation period in eastern North America, and historical factors associated with this recent recolonization of damselflies into temperate zones may have important implications on the structure of contemporary odonate communities (McPeek and Brown 2000, Turgeon and McPeek 2002, Turgeon et al. 2005. ...
... Moreover, the evolutionary history of particular odonate lineages has likely had a strong influence on communities located in temperate and boreal regions (McPeek and Brown 2000, Turgeon and McPeek 2002, Turgeon et al. 2005. A highly studied genus of damselflies, Enallagma, experienced a recent radiation during the last glaciation period in eastern North America, and historical factors associated with this recent recolonization of damselflies into temperate zones may have important implications on the structure of contemporary odonate communities (McPeek and Brown 2000, Turgeon and McPeek 2002, Turgeon et al. 2005. ...
... Based on the extent of the boreal and temperate climates and the limited available literature on odonate radiations and migration in eastern North America, we estimated the pool of species that have the potential to disperse and persist in Qu ebec. Previous phylogenetic studies have shown that there is a distinct eastern North American odonate species pool as a result of different refugia during the last Pleistocene glaciation (McPeek and Brown 2000, Turgeon and McPeek 2002, Turgeon et al. 2005. This full species pool comprised 173 species. ...
Historical, evolutionary, and ecological processes jointly shape the structure of communities, and the relative influence of such process may vary from one region to another. Nevertheless, much of community ecology focuses on one or several communities in a given region. To assess the relative importance and the context‐dependency of processes shaping communities, studies in community ecology must be conducted across regions and along broad‐scale environmental gradients. Regionally, historical colonization and extinction events, as well as diversification, can influence community structure by shaping the pool of potential community members (i.e., the regional species pool). Locally, a suite of deterministic and stochastic processes can influence community structure. We constructed a large time‐calibrated phylogenetic tree for North American odonates and used analyses of phylogenetic community structure with explicit species pool definitions to assess the predominant processes structuring assemblages along a north–south environmental gradient spanning two biomes and 8° of latitude in eastern Canada. Phylogenetic analyses of 39 lentic (i.e., lake) odonate communities revealed that co‐occurring species were on average more closely related than expected by chance, but only in the temperate biome. In addition, site‐to‐site variation in phylogenetic structure across the temperate and boreal biomes was most strongly related to variation in water pH. The most alkaline lakes were in the temperate biome and were also the most phylogenetically clustered, suggesting that water pH acts as a main environmental filter of odonate communities. An alternative explanation was that the recent radiation of damselflies increased the diversity of this group relative to that of dragonflies in the temperate species pool, thereby leaving a signature of clustering in that biome. However, our comparative null model analyses with explicit species pool definitions at least partially ruled out this explanation. Somewhat contrary to previous hypotheses regarding the assembly of odonate communities, our results suggest that stochastic processes alone cannot account for community structure in odonates and that deterministic, niche‐based processes have a strong influence.
... An elegant study system to explicitly quantify predator-driven survival selection on escape behaviour is provided by the North American species of the damselfly genus Enallagma. Most Enallagma species occur in lakes containing fish (hereafter called fish lakes), the ancestral habitat, and three independent invasions have occurred to fishless lakes where large predatory dragonfly larvae are the top predators (hereafter called dragonfly lakes) (Brown, McPeek, & May, 2000;Turgeon, Stoks, Thum, Brown, & McPeek, 2005). These invasions into dragonfly lakes were associated with the evolution of higher values for two related escape traits: swimming propensity and escape swimming speed (McPeek, 1999;McPeek et al., 1996). ...
... Here, we present the results of two field enclosure experiments in which we quantified selection pressures on both escape traits (swimming propensity and swimming speed) in two fish-lake Enallagma species in the ancestral fish lakes and in the derived dragonfly lakes to test for different patterns of directional selection between habitats with different predator assemblages. We studied two fish-lake species, Enallagma geminatum and Enallagma hageni Turgeon et al., 2005), that represent the two clades (and the associated ancestral phenotypes) that independently gave rise to the dragonfly-lake Enallagma. We quantified selection by fish on these traits in their natural fish-lake habitat and by dragonfly predators in the derived dragonfly lakes. ...
... We quantified selection by fish on these traits in their natural fish-lake habitat and by dragonfly predators in the derived dragonfly lakes. These coupled experiments thus simulate the initial change in phenotypic selection regime presumably experienced by the ancestral fish-lake species when they invaded dragonfly lakes within the last 20 000 years Turgeon et al., 2005). We expected fish predation to select for a lower propensity to swim but not to impose selection on escape swimming speed, while we expected dragonfly predation to select for a higher propensity to swim and a higher escape swimming speed. ...
Despite the many study systems in which predation has played a major role in phenotypic diversification and speciation, the underlying selective regimes imposed by different predator assemblages have rarely been quantified. We did so for the damselfly genus Enallagma which strongly diverged in antipredator traits when the ancestral species occupying lakes containing fish (hereafter fish lakes) repeatedly invaded fishless lakes with dragonfly larvae as top predators (hereafter dragonfly lakes). In two selection experiments in field enclosures we quantified the selection on two key escape traits of two fish-lake Enallagma species associated with survival selection by fish in the ancestral fish lakes and by dragonfly predators in the invaded fishless, dragonfly lakes. In accordance with the different hunting modes, fish imposed selection for a decreased swimming propensity while dragonfly larvae imposed selection for increased swimming speed in one of the two species. In two complementary quantitative genetic rearing experiments, we found relatively low but significant broad-sense heritabilities for both escape traits. Integrating these estimates for the selection coefficients and the heritabilities suggests that the evolutionary increase in swimming speed associated with the habitat shift may have occurred rapidly. Our study suggests that the phenotypic evolution of ecologically important traits related to habitat shifts may occur at an ecological timescale.
... Enallagma damselfly species experience these different predation environments. Enallagma are derived from ancestral populations evolving under fish as the dominant predator (Stoks, McPeek, & Mitchell, 2003;Turgeon, Stoks, Thum, Brown, & McPeek, 2005). In northeastern North America, related species have adaptively diverged between pond environments because of strong trade-offs in antipredator behaviours (Johnson & Crowley, 1980;McPeek, 1989McPeek, , 1990aMcPeek, , 1996Turgeon & McPeek, 2002). ...
... Live larvae were identified in the laboratory using the Odonata Larvae of Michigan key (Bright & O'Brien, 1999). Enallagma signatum are reliably distinguishable based on larval morphology, but live larvae of other Enallagma species are not reliably distinguished among certain species pairs by larval morphology or with neutral loci (Reynolds, Hajibabaei, & Robinson, 2012;Turgeon & McPeek, 2002;Turgeon et al., 2005). Following prior practice, we grouped E. boreale with E. annexum, and E. ebrium with E. hageni (McPeek, 1990b;Stoks et al., 2003;Turgeon et al., 2005). ...
... Enallagma signatum are reliably distinguishable based on larval morphology, but live larvae of other Enallagma species are not reliably distinguished among certain species pairs by larval morphology or with neutral loci (Reynolds, Hajibabaei, & Robinson, 2012;Turgeon & McPeek, 2002;Turgeon et al., 2005). Following prior practice, we grouped E. boreale with E. annexum, and E. ebrium with E. hageni (McPeek, 1990b;Stoks et al., 2003;Turgeon et al., 2005). ...
Plastic behavioural responses by individuals to different conditions and consistent individual differences in mean behaviour across situations both contribute to variation in a population. The relationship between behavioural plasticity and consistent individual differences is not clearly understood but may help predict personality variation in animals. High variation in mean behaviour and low variation in individual plastic responses will tend to maintain the rank order of individuals across situations and so permit consistent individual differences. Conversely, low variation in mean behaviour and high variation in plastic responses, by changing the rank orders of individuals, will erode consistent individual differences. Thus, selection that reduces variation in individual plastic responses should increase the opportunity for consistent individual differences in a population. We tested for relationships between heterogeneous predation regimes, the mean and variance of behavioural plasticity and consistent individual differences among three species groups of larval damselflies. Larvae of Enallagma signatum probably face consistent predation from fish over successive generations, whereas Enallagma ebrium/hageni and Enallagma annexum/boreale face a changing predation regime over generations either from fish or larval dragonflies. The behavioural reaction norms of larvae in repeated exposure trials to cues from a predatory fish, dragonfly larvae or no predator differed between species groups. Enallagma ebrium/hageni expressed the most consistent plastic response to predator cues, less variability in plasticity and greater consistent individual differences across cues compared to more variable plastic responses and low consistent individual differences in E. signatum. Selection on behavioural plasticity may enhance consistent individual differences in E. ebrium/hageni whereas relaxing selection on plasticity may reduce consistent individual differences in E.signatum. More generally, selection on plastic behaviour may enhance behavioural types while selection on mean behaviour may reduce behavioural types in animal populations.
... Historical events may have had drastic effects on the geographic, demographic, ecological, genetic and social conditions of populations, thereby promoting favourable conditions for diversification, and even speciation (e.g. Pielou, 1991;Hewitt, 2004;Turgeon et al., 2005;Keyghobadi, 2007). Past stochastic events during glacial and inter-glacial periods can thus be expected to have played an important role in the spread of alleles, including alleles that code for colour. ...
... This pattern is believed to be the result of range expansions from glacial refugia (e.g. Taberlet, 1998;Hewitt, 2001;Turgeon et al., 2005;Heilveil & Berlocher, 2006;Eckert et al., 2008). Moreover, pronounced population divergence at the range limits are also predicted for other traits (e.g. ...
... These stochastic events, together with the absence of harassment selection, may result in Western populations with high andromorph frequencies nowadays. We stress that this does not exclude the possibility of sexual (e.g.Van Gossum et al., 2007a; and/or natural selection (e.g.Hammers & Van Gossum, 2008; shaping the observed spatial pattern of female morph frequencies, but instead suggest a role for multiple mechanisms, including historical events.Our study shows that the genetic variability in N. gracilis is low, and even lower in N. irene, compared to other African and North American damselfly species (where the same molecular markers were investigated) (Pseudagrion spp.:Rach et al., 2008; Enallagma spp.: Turgeon & McPeek, 2002;Turgeon et al., 2005). Indeed, in contrast to our expectations, overall genetic variability in N. irene was nearly three times lower than in its sister species N. gracilis, despite N. gracilis being monomorphic and showing a much smaller distribution range. ...
The coexistence of two or more heritable morphs within species’ populations is commonly observed in nature, a phenomenon known as polymorphism. Intriguingly, such polymorphisms are often restricted to only the male or only the female sex (intra-sexual polymorphisms). The phenomenon is paradoxical to evolutionary biologists because selection is expected to favor not more than only a single phenotype. Hence, questions related to whether and how different morphs can be maintained are subject to classic and long-standing debates. Theory posits that longterm maintenance of polymorphisms is possible only under a restricted set of conditions, but exact mechanisms remain poorly understood in many cases.
The overall objective of my PhD thesis is to explore several mechanisms that may help to explain maintenance of intra-sexual polymorphism. I selected female polymorphic damselflies as my model system, in which two or three female morphs can easily be distinguished based on their body coloration, while only a single male type occurs. The coexistence of these female morphs is commonly explained as a counter adaptation to reduce costly male sexual harassment. However, observations in several species indicate extreme and often gradually varying morph frequencies across populations. As it appears from recent work, social interactions alone appear insufficient to thoroughly explain this geographic variation in female morph frequencies, thus questioning the exact mechanisms underlying this polymorphism. Additional mechanisms have been suggested, including divergent selection. Specifically, one morph may be favored over the others depending on a given set of environmental conditions like solar radiation, ambient temperature or precipitation
regimes.
In my thesis, I first ask to what extend geographic variation in morph frequencies is related to numerous of investigated biotic and abiotic variables and to the genetic variability across populations. Given the lack of spatial organization in morph frequencies along a continuous 1100 km transect, the limited explanatory power by the investigated ecological variables and the extremely low genetic variation in a region characterized by atypical morph frequencies across sites, I suggest that historical and present-day stochastic processes may play a more prominent role than previously acknowledged in shaping biogeographical patterns in morph frequencies.
Next to the above described exploration of biogeographical patterns and covarying factors, the observed frequency and density variation across sites itself offers ample opportunity to evaluate and test predictions based on social interactions. Besides body coloration, I found that female morphs differ in multiple traits like behavior, morphology, immune function, energy reserves and fecundity. This made me suggest that correlational selection may favor optimal trait combinations in which female morphs maximize fitness in alternative ways. When including the entire range of female morph frequencies, I show under experimental and natural conditions that males bias their mating preference towards the most common morph within a given population. This biased mating behaviour most likely translates into dissimilar harassment levels between female morphs, causing negative frequency-dependent costs in terms of female morph fecundity. I further show geographic variation in morph-specific behavioral harassment resistance strategies, which may as well be related to the social environment.
Furthermore, one female morph (andromorph) shows remarkable phenotypic resemblance with conspecific males. In line with ideas on intra-specific mimicry, I show that andromorphs share more morphological similarities with males compared with other females. Moreover, consistent with expectations based on signal detection theory, this mimetic similarity increases with the proportion of andromorphs (mimics) to the males (models). Because investigated short- and long-term weather parameters did not differently affect behavioral and physiological traits of female morphs and because of the low predictive power of such parameters in explaining geographic morph frequency variation, I indicate a minor role for abiotic conditions in explaining the maintenance of this polymorphism. Instead, I conclude that frequency- and densitydependent selection imposed by male harassment acting within populations may, at least in part, keep this polymorphism in balance. In addition, I point at underestimated stochastic effects that may cancel out effects of selection under some conditions.
... Because speciation events can be driven by both ecological and non-ecological mechanisms (Rundell and Price 2009;Wellenreuther and Sánchez-Guillén 2016), these events can have ramifications (see Chapter 15) for how the resulting communities are structured via deterministic niche or stochastic neutral-based processes (McPeek 2008a;Mittelbach and Schemske 2015). Over millennial timescales and longer, phylogeographic studies have revealed the signature of climate upheaval on the assembly dynamics of communities (Turgeon et al., 2005). Likewise, shifts into different community types over both these timescales (because of adaptive evolution in response to ecological interactions) has also generated considerable changes in community structure McPeek 2008a;Start 2018). ...
... Differences in predator regimes have repeatedly generated parallel adaptive differences in phenotypic traits that mediate predator-prey interactions (Johansson and Mikolajewski 2008). Phylogenetic reconstructions indicate that micro-evolutionary driven habitat shifts between fish and dragonfly lakes have occurred independently several times in both damselfly McPeek 2000;Turgeon et al., 2005;Stoks and McPeek 2006;Siepielski and Beaulieu 2017) and dragonfly clades (Mikolajewski and Johansson 2004;Mikolajewski et al., 2006;Johansson and Mikolajewski 2008;Start 2018). Such adaptive shifts could have arisen during ecological speciation events to fill ecological niches, or post-speciation. ...
This research-level text documents the latest advances in odonate biology and relates these to a broader ecological and evolutionary research agenda. Despite being one of the smallest insect orders, dragonflies offer a number of advantages for both laboratory and field studies. In fact, they continue to make a crucial contribution to the advancement of our broader understanding of insect ecology and evolution. This new edition provides a critical summary of the major advances in these fields. Contributions from many of the leading researchers in dragonfly biology offer new perspectives and paradigms as well as additional unpublished data. The editors have carefully assembled a mix of theoretical and applied chapters (including those addressing conservation and monitoring) as well as a balance of emerging (e.g. molecular evolution) and established research topics, providing suggestions for future study in each case. This accessible text is not about dragonflies per se, but rather an essential source of knowledge that describes how different sets of evolutionary and ecological principles/ideas have been tested on a particular taxon. This second edition of Dragonflies and Damselflies is suitable for graduate students and researchers in entomology, evolutionary biology, population and behavioral ecology, community ecology, and conservation biology. It will be of particular interest and use to those working on insects and an indispensable reference text for odonate biologists.
... 16 (Johnson 2012). 17 (Turgeon et al., 2005). 18 (Donnelly 2008). ...
... Suvorov and colleagues (2022) detected introgressive hybridization events in the phylogenetic history of odonates, mainly at the inter-suborder level (anisozygopterans) and the interfamilial level (Gomphidae+Petaluridae, Aeshnidae, and Libellulidae). In Enallagma and Ischnura damselflies, studies detected signals of past asymmetric hybridization between species (in different clades) during radiation (Turgeon et al., 2005;Sánchez-Guillén et al., 2020). In fact, two species with putative hybrid origins have already been identified: in Enallagma (E. ...
This research-level text documents the latest advances in odonate biology and relates these to a broader ecological and evolutionary research agenda. Despite being one of the smallest insect orders, dragonflies offer a number of advantages for both laboratory and field studies. In fact, they continue to make a crucial contribution to the advancement of our broader understanding of insect ecology and evolution. This new edition provides a critical summary of the major advances in these fields. Contributions from many of the leading researchers in dragonfly biology offer new perspectives and paradigms as well as additional unpublished data. The editors have carefully assembled a mix of theoretical and applied chapters (including those addressing conservation and monitoring) as well as a balance of emerging (e.g. molecular evolution) and established research topics, providing suggestions for future study in each case. This accessible text is not about dragonflies per se, but rather an essential source of knowledge that describes how different sets of evolutionary and ecological principles/ideas have been tested on a particular taxon. This second edition of Dragonflies and Damselflies is suitable for graduate students and researchers in entomology, evolutionary biology, population and behavioral ecology, community ecology, and conservation biology. It will be of particular interest and use to those working on insects and an indispensable reference text for odonate biologists.
... This is an important constraint to interspecific reproduction in Odonata (Monetti, Sánchez-Guillén, & Cordero Rivera, 2002;Paulson, 1974;Sánchez-Guillén, Wellenreuther, Cordero-Rivera, & Hansson, 2011). Under sexual selection, when females of one species are locally rare and cannot find suitable (i.e., conspecific) males, they eventually mate with males of the locally common species (Turgeon, Stoks, Thum, Brown, & McPeek, 2005). ...
... The Ima2 analysis (Figure 4a) revealed the presence of asymmetric gene flow from C. trinacriae to C. boltonii. Unidirectional hybridization has also been observed in the Odonata genera Enallagma and Ischnura (Sánchez-Guillén et al., 2011;Turgeon et al., 2005), and for ...
Two Cordulegaster dragonflies present in Italy, the Palaearctic and northern distributed Cordulegaster boltonii and the endemic to the south of the peninsula Cordulegaster trinacriae, meet in central Italy and give rise to individuals of intermediate morphology. By means of mitochondrial and nuclear markers and of Geometric Morphometrics applied to sexual appendages, we defined i) the geographical boundaries between the two species in Italy and ii) we determined the presence, the extent, and the genetic characteristics of the hybridization. Genetic data evidenced asymmetric hybridization with the males of C. trinacriae able to mate both interspecifically and intraspecifically. The results contrast with expectations under neutral gene introgression and sexual selection. This data, along with the morphological evidence of significant differences in size and shape of sexual appendages between the males of the two species, seem indicative of the role of mechanical constraints in intraspecific matings. The origin of the two species is dated about to 1.32 Mya and the hybridization resulted related to range expansion of the two species after Last Glacial Maximum and this led to the secondary contact between the two taxa in central Italy. At last, our results indicate that the range of C. trinacriae, a threatened and protected species, has been moving northward probably driven by climate changes. As a result, the latter species is currently intruding into the range of C. boltonii. The hybrid area is quite extended and the hybrids seem well adapted to the environment. From a conservation point of view, even if C. trinacriae has a strong genetic identity, the discovery of hybridization between the two species should be considered in a future species management.
... We measure 19 potential preand postzygotic isolating barriers between Enallagma anna and E. carunculatum, two species that diverged from a common ancestor sometime in the last ß250,000 generations (McPeek et al. 2008;Callahan and McPeek 2016) and co-occur over much of the western United States (Westfall and May 2006). Both species have identical ecologies and overall morphologies (Turgeon et al. 2005;McPeek et al. 2009), but display conspicuous differences in the size and shape of the male cerci and female mesostigmal plates (Fig. 1). We quantify variation in male and female reproductive structure morphologies, distinguish mechanical and tactile premating incompatibilities, estimate the cumulative strengths of multiple reproductive barriers, and independently test predictions of mechanical and tactile isolation hypotheses (Richards and Robson 1926;Shapiro and Porter 1989). ...
... The finding that some E. anna females mated with hybrid males, but none mated with E. carunculatum males suggests that females display some latitude in their preferences and are more likely to refuse males whose cercus morphology greatly deviates from a conspecific phenotype. Although incomplete mechanical isolation has been documented in several Enallagma species pairs, few cases of hybridization are known, based on morphological or genetic evidence (Catling 2001;Turgeon et al. 2005;Donnelly 2008). This suggests that even with incomplete mechanical isolation, tactile isolation might prevent interbreeding among most Enallagma species. ...
External male reproductive structures have received considerable attention as a cause of reproductive isolation (RI), because the morphology of these structures often evolves rapidly between populations. This rapid evolution presents the potential for mechanical incompatibilities with heterospecific female structures during mating and could thus prevent interbreeding between nascent species. Although such mechanical incompatibilities have received little empirical support as a common cause of RI, the potential for mismatch of reproductive structures to cause RI due to incompatible species-specific tactile cues has not been tested. We tested the importance of mechanical and tactile incompatibilities in RI between Enallagma anna and E. carunculatum, two damselfly species that diverged within the past ∼250,000 years and currently hybridize in a sympatric region. We quantified 19 prezygotic and postzygotic RI barriers using both naturally occurring and lab-reared damselflies. We found incomplete mechanical isolation between the two pure species and between hybrid males and pure species females. Interestingly, in species pairs for which mechanical isolation was incomplete, females showed greater resistance and refusal to mate with hybrid or heterospecific males compared to conspecific males. This observation suggests that tactile incompatibilities involving male reproductive structures can influence female mating decisions and form a strong barrier to gene flow in early stages of speciation. This article is protected by copyright. All rights reserved
... Taxonomically interesting was the coexistence in the studied area, but not at the same localities of Enallagma cyathigerum and E. risi, the latter at the northernmost known locality. The fact of clear spatial separation and at most minimum degree of intergrading (if any) of these two taxa suggests their full species status that agrees with morphological and recent molecular data TURGEON et al., 2005). ...
... Hence, during our expedition we faced a correlation between the morphological characteristics distinguishing the two taxa and the habitat type, and also the presence/absence of the variable abdominal melanisation (the last element, however, may be only a consequence of different habitat conditions). This correlation supports recent morphological and molecular datasuggesting that these taxa are bona speciesTURGEON et al., 2005). However, the presumed reproductive isolation may be incomplete, since among 30 collected males of Enallagma two individuals looked intermediate between the two taxa as they had only a very narrow part of the pale tuber- ...
Results of the studies of odonate fauna, carried out in July 2006 in the odonatologically almost unexplored Vasyugan Plain, are presented. The studies concentrated in the northern and northeastern parts of the largest bog in the world, the Vasyugan Bog, and its surroundings. Large primeval complexes of Sphagnum bogs and fens and other accompanying habitats, man-made as well, were studied. 25 localities are briefly described and the occurrence of 35 recorded spp. is commented. Due to almost total absence of typically East Palaearctic spp. (only Shaogomphus postocularis found), the aspect of the odon. fauna in the studied area is similar to a certain degree to that known from central and eastern Europe, but with some differences in the species composition, abundance of many spp. and their habitat preferences. In Coenagrion puella, C. pulchellum, Enallagma risi, Nehalennia speciosa, Gomphus vulgatissimus, Shaogomphus postocularis, Somatochlora flavomaculata, Leucorrhinia albifrons, and L. pectoralis, the northern limit of their distribution appears further N than it was previously known. This suggests that the actual northern range limit of some of these species in W Siberia does not descend as sharply to the S as it was expected. The first known site of S. postocularis W of the Ob' river and on a perfect plain is also worth noticing. Among the most remarkable discoveries was the regular, area-wide occurrence of several previously poorly known in Siberia spp., such as N. speciosa, Aeshna subarctica, G. vulgatissimus and S. flavomaculata. Taxonomically interesting is the coexistence, in the studied area but not at the same localities, of two taxa considered as subspecies or separate species, E. c. cyathigerum and E. (c.?) risi. The fact of clear spatial separation and at most a minimum degree of intergrading (if any) of these 2 taxa suggests their full species status which would agree with morphological and recent molecular data. The regular and not rare presence of 2 androchrome Calopteryx splendens ♀ forms and ♂ ♂ with the wings coloured to the tips, as well as the occurrence of brownish wing 'smoking' of many ♀ S. flavomaculata and S. arctica are peculiar features of the Vasyugan odon. aspect. The ♂ segregation in the 'triangle' of peat bog aeshnids, Aeshna crenata, A. juncea and A. subarctica, is described and discussed. Between A. juncea and A. subarctica it was very advanced, partially spatial and partially weather/temporal, between A. crenata and A. subarctica almost complete, spatial, and between A. crenata and A. juncea advanced, weather/ temporal. These observations confirm the dominant position of A. crenata over the water table, and also suggest the lack of crenata-dominance off the water table. The reliability of adult diagnostic features, more and less commonly used to distinguish between A. subarctica and A. juncea, is discussed.
... Based on its biogeography, the radiation of the North American Enallagma species includes two monophyletic clades: the southern 'hageni' and the northern 'carunculatum' clades (Brown, McPeek, and May 2000). Data indicate that about half of all extant Enallagma species have arisen sometime within the last 250,000 years from these two radiating lineages, and most species arose within the last ~15,000 years (Brown, McPeek, and May 2000;Turgeon and McPeek 2002;Turgeon et al. 2005). Ischnura ( Fig. 1 E and F) species ages range between 25-45 Mya (Bechly 1998), and encompasses around 70 species that are distributed on all continents, with the exception of Antarctica (Dijkstra and Kalkman 2012). ...
... Thus, the morphologies of secondary male and female structures appear to be critical for mate recognition and acceptance, underscoring that evolution of mechanical isolation has been fundamental in the radiation of this group. The finding that mechanical isolation is, however, not complete between all species indicates past asymmetric hybridization, which is consistent with the finding that species are genetically compatible and, therefore, could hybridise (Turgeon et al. 2005). ...
Adaptive radiations have long served as living libraries to study the build-up of species richness, however, they do not provide good models for radiations that exhibit negligible adaptive disparity. Here we review work on damselflies to argue that non-adaptive mechanisms were predominant in the radiation of this group and have driven species divergence through sexual selection arising from male–female mating interactions. Three damselfly genera (Calopteryx, Enallagma and Ischnura) are highlighted and the extent of (i) adaptive ecological divergence in niche use and (ii) non-adaptive differentiation in characters associated with reproduction (e.g. sexual morphology and behaviours) evaluated. We demonstrate that species diversification in the genus Calopteryx is caused by non-adaptive divergence in colouration and behaviour affecting premating isolation, and structural differentiation in reproductive morphology affecting postmating isolation. Similarly, the vast majority of diversification events in the sister genera Enallagma and Ischnura are entirely driven by differentiation in genital structures used in species recognition. The finding that closely related species can show negligible ecological differences yet are completely reproductively isolated suggests that the evolution of reproductive isolation can be uncoupled from niche-based divergent natural selection, challenging traditional niche models of species coexistence.This article is protected by copyright. All rights reserved.
... Aeshna interrupta is another good example of a species with widespread geographical variation . Genetic work may also help determine the relationships among Palaearctic and Nearctic taxa, as was done with the separation of the Nearctic Enallagma annexum Hagen from the Palaeartic E. cyathigerum (Charpentier) (Turgeon et al. 2005). ...
... cyathigerum) and a New World species (E. annexum) (Turgeon et al. 2005). Enallagma clausum (Fig. 5) is a western species characteristic of alkaline ponds and lakes in dry grasslands in British Columbia and the Prairies, where it can be extremely abundant, even at sites so salty that other odonates are absent. ...
The Odonata are energetic aerial predators of other insects; the aquatic larvae are voracious predators of invertebrates and small vertebrates. As of 2010, 5,952 species of the order were described worldwide; 211 species are known from Canada. Grasslands across the country support about 59% of the national fauna. A checklist and systematic overview of 124 species in nine families are presented. Species totals in these families are as follows:, 37. The geographical ranges of the species are defi ned and summarized; according to the defi nitions herein, 20 species have boreal ranges, 17 are transition species, 12 are Cordilleran, 1 is Pacifi c coastal, 10 are western, 4 are more or less restricted to the Great Plains, 16 have southern ranges, 38 are considered eastern, and 6 are widespread species. A summary of studies on grassland Odonata and recommendations for inventory and taxonomic research are provided. The geographical scope of the Canadian grassland fauna is described briefl y with respect to lotic and lentic habitats in grasslands of the Cordillera, the Great Plains, and southern Ontario. Résumé. Les odonates sont de féroces prédateurs aériens d'autres insectes ; leurs larves aquatiques sont aussi des prédateurs voraces d'autres invertébrés et petits vertébrés. En 2010, 5 952espèces d'odonates avaient été décrites dans le monde. De ce nombre, 211 sont connues au Canada. Environ 59 % des odonates de la faune canadienne s'observent dans les prairies. Ce chapitre présente une liste et un aperçu de la systématique de 124 espèces, réparties en neuf familles comme suit: espèces sont par ailleurs défi nies, ce qui permet de conclure que 20 espèces ont une aire de répartition boréale, 17 sont des espèces de transition, 12 vivent dans la Cordillère, 1 vit sur la côte du Pacifi que, 10 sont occidentales, 4 sont plus ou moins limitées aux Grandes Plaines, 16 ont une aire de répartition méridionale, 38 sont considérées orientales, et 6 sont des espèces largement répandues. Le chapitre présente un résumé des études réalisées sur les odonates des prairies ainsi que des recommandations concernant les travaux d'inventaire et les études taxonomiques à réaliser. La portée géographique de la faune de la prairie canadienne est brièvement décrite en ce qui a trait aux habitats lotiques et lentiques des prairies qui se trouvent dans la Cordillère, dans les Grandes Plaines et dans le sud de l'Ontario.
... Enallagma cyathigerum (Charpentier) was once considered the only Holarctic member of the genus Enallagma and the family Coenagrionidae, but it has been split into two species, one in the Old World, one in the New World. Enallagma cyathigerum is the original Eurasian taxon; the Nearctic populations are now called E. annexum (Turgeon et al. 2005). ...
Canada has lost three important odonatologists since the first edition of this list was published in 2005: Gordon Pritchard, University of Calgary biology professor and internationally active odonate researcher (Cannings 2013); Paul Brunelle, leader of the massive inventory of Odonata in the Maritime Provinces (McAlpine 2020a, b, c) and co-author of the first edition of this checklist; and Raymond Hutchinson, who made huge contributions to Québec and Canadian odonatology over the past five decades (Savard 2021). We dedicate this work to them.
... The males exhibited a trend of lateral melanisation of the abdomen (the presence of black stripes and spots, often irregular or asymmetric), varying from none ( Fig. 18a-b) through medium (Fig. 18c) to considerable (Fig. 18d), which frequently occurs in this subspecies in the taiga zone (Kosterin & Zaika 2010;Onishko & Kosterin 2021), The same was observed in 2002 (Kosterin 2004a). By the way, three of the specimens collected in 2002 were involved into sequencing of the fragment of the mitochondrial DNA from COI to COII genes and AFLP analysis by Turgeon et al. (2005). Surprisingly, both analyses revealed their being most close to specimens of "E. ...
Odonata of the Aldan Ulus (District) of Sakha Republic (Yakutia), East Siberia, Russia, were studied in late June – early July 2022 for the second time, 20 years after the
nalogous previous study (Kosterin 2004a), partly in the same localities. This time 20 species were found, that is 1.5 times more than 13 species on the previous study. This increase could be an effect of the current climate amelioration but no northward range extensions were registered, all species being known in Yakutia more northerly for quite a long time. Ten species were found in 2022 but not in 2002 (Coenagrion armatum, C. glaciale, C. hylas, C. lanceolatum, Erythromma najas, Aeshna crenata, A.
uncea, Ophiogomphus obscurus, Leucorrhinia intermedia, Sympetrum flaveolum), while three species were found in 2002 but not this time (Aeshna caerulea, Nihonogomphus ruptus and Somatochlora sahlbergi). In total, 23 species have been registered in Aldan Ulus up to date. Variation in Enallagma cyathigerum, Erythromma najas, Somatochlora exuberata and Leucorrhinia orientalis is briefly discussed. Mass emergence of O. obscurus from the Aldan River on a rainy day (and even during
showers) following a period of hot weather was observed and discussed.
... Some molecular studies of extant insect taxa suggest that speciation in the Pleistocene and Holocene was common (e.g. Barraclough and Vogler 2002;Ribera and Vogler 2004;Cardoso and Vogler 2005;Turgeon et al. 2005;Previšićet al. 2009;Hidalgo-Galiana et al. 2014;Torres-Mantelet et al. 2020), conflicting with the fossil record. Previous studies have suggested that geographical differences may account for this disparity (Ribera and Vogler 2004;Abellán et al. 2011). ...
The Middle-Late Pennsylvanian Subperiod was marked by recurrent glacial-interglacial cycles superimposed on a longer-term trend of increasing aridity. Wetland and drought-tolerant floras responded with repeated migrations in the tropics, and a major plant turnover occurred in swamp ecosystems in parts of Euramerica near the Middle-Late Pennsylvanian boundary. However, the corresponding ecological and evolutionary responses of insects and other terrestrial arthropods are poorly understood. Here, we review the record of plant-arthropod interactions and analyse origination and extinction rates of insects during the Middle-Late Pennsylvanian. Although preliminary, plant-arthropod associations broadly persist through the Middle-Late Pennsylvanian boundary, and new damage types and host-plant associations first appear in the Late Pennsylvanian, possibly related to increased availability of accessible vascular and foliar tissues associated the shift from arborescent lycopsid to tree and seed fern dominance in Euramerican wetlands. Likewise, our analysis of the insect body fossil record does not suggest especially high rates of origination or extinction during this interval. Together, these results suggest that insects did not suffer major extinctions during the Middle-Late Pennsylvanian, despite short- and long-term changes in climate and environmental conditions.
Supplementary material at https://doi.org/10.6084/m9.figshare.c.6280586
... The shape of the LTT plot may help to distinguish a basal extinction from a tip radiation, because the mass extinction can result in an antisigmoidal shape of the curve with distinct plateau and subsequent sharp upturn in slope (Harvey et al., 1994;Crisp & Cook, 2009). The slope of LTT plot for the Analges is not antisigmoidal and becomes distinctly steeper without preceding plateau (Fig. 4B), which can be interpreted as an explosive radiation (Turgeon et al., 2005;McKenna & Farrell, 2006;Crisp & Cook, 2009). This radiation coincides with the origin of the crown in the Analges clade. ...
Mites of the genus Analges (Acariformes: Analgidae) inhabit the down feathers of passeriform birds. The evolutionary history of Analges and the co-phylogentic relationships between these mites and their hosts are unknown. Our phylogenetic analysis supported the monophyly of the genus, but it did not support previous taxonomic hypotheses subdividing the genus into the subgenera Analges and Analgopsis or arranging some species into the A. chelopus and A. passerinus species groups. Molecular data reveal seven new species inhabiting Eurasian passerines and support the existence of several multi-host species. According to molecular dating, the origin of the Analges (c. 41 Mya) coincided with the Eocene diversification of Passerida into Sylvioidea and Muscicapoidea–Passeroidea. The initial diversification of Analges took place on the Muscicapoidea clade, while remaining passerine superfamilies appear to have been colonized because of host-switching. Co-speciation appears to be relatively common among Analges species and their hosts, but the most striking pattern in the co-phylogenetic scenario involves numerous complete host-switches, spreads and several failures to speciate. The mechanism of long-term gene-flow among different populations of multi-host Analges species is enigmatic and difficult to resolve. Probably, in some cases mites could be transferred between birds via feathers used as nest material.
... The shape of the LTT plot may help to distinguish a basal extinction from a tip radiation, because the mass extinction can result in an antisigmoidal shape of the curve with distinct plateau and subsequent sharp upturn in slope (Harvey et al., 1994;Crisp & Cook, 2009). The slope of LTT plot for the Analges is not antisigmoidal and becomes distinctly steeper without preceding plateau (Fig. 4B), which can be interpreted as an explosive radiation (Turgeon et al., 2005;McKenna & Farrell, 2006;Crisp & Cook, 2009). This radiation coincides with the origin of the crown in the Analges clade. ...
Mites of the genus Analges (Acariformes: Analgidae) inhabit the down feathers of passeriform birds. The evolutionary history of Analges and the co-phylogentic relationships between these mites and their hosts are unknown. Our phylogenetic analysis supported the monophyly of the genus, but it did not support previous taxonomic hypotheses subdividing the genus into the subgenera Analges and Analgopsis or arranging some species into the A. chelopus and A. passerinus species groups. Molecular data reveal seven new species inhabiting Eurasian passerines and support the existence of several multi-host species. According to molecular dating, the origin of the Analges (c. 41 Mya) coincided with the Eocene diversification of Passerida into Sylvioidea and Muscicapoidea–Passeroidea. The initial diversification of Analges took place on the Muscicapoidea clade, while remaining passerine superfamilies appear to have been colonized because of host-switching. Co-speciation appears to be relatively common among Analges species and their hosts, but the most striking pattern in the co-phylogenetic scenario involves numerous complete host-switches, spreads and several failures to speciate. The mechanism of long-term gene-flow among different populations of multi-host Analges species is enigmatic and difficult to resolve. Probably, in some cases mites could be transferred between birds via feathers used as nest material.
... If morph loss in the ancestor of I. posita resulted from genetic drift during a period of allopatry and population contraction, it must then have been followed by rapid and recent range expansion. While this hypothesis remains to be investigated for I. posita, closely related and young sympatric taxa in Enallagma are thought to be the result of rapid speciation and range expansion after glacial retreat in the Quaternary (McPeek and Gavrilets, 2006;Turgeon et al., 2005). Range size in millions of km 2 Probability of female polymorphism Fig. 5. Probability of species having female polymorphism in relation to the species geographic range size, estimated in millions of squared kilometres. ...
Colour polymorphisms are popular study systems among biologists interested in evolutionary dynamics, genomics, sexual selection and sexual conflict. In many damselfly groups, such as in the globally distributed genus Ischnura (forktails), sex-limited female colour polymorphisms occur in multiple species. Female-polymorphic species contain two or three female morphs, one of which phenotypically matches the male (androchrome or male mimic) and the other(s) which are phenotypically distinct from the male (heterochrome). These female colour polymorphisms are thought to be maintained by frequency-dependent sexual conflict, but their macroevolutionary histories are unknown, due to the lack of a robust molecular phylogeny. Here, we present the first time-calibrated phylogeny of Ischnura, using a multispecies coalescent approach (StarBEAST2) and incorporating both molecular and fossil data for 41 extant species (55% of the genus). We estimate the age of Ischnura to be between 13.8 and 23.4 millions of years, i.e. Miocene. We infer the ancestral state of this genus as female monomorphism with heterochrome females, with multiple gains and losses of female polymorphisms, evidence of trans-species female polymorphisms and a significant positive relationship between female polymorphism incidence and current geographic range size. Our study provides a robust phylogenetic framework for future research on the dynamic macroevolutionary history of this clade with its extraordinary diversity of sex-limited female polymorphisms.
... To achieve such rates, however, one must completely exclude the possibility of several species surviving that desiccation in small, permanent pools. An additional example is the rapid divergence of Enallagma damselflies, which have added 23 new species from seven lineages in the last 250,000 years (Turgeon et al., 2005). In contrast are lineages such as Ginkgo, which appears to have changed little since the Jurassic (Zhou and Zheng, 2003). ...
... To achieve such rates, however, one must completely exclude the possibility of several species surviving that desiccation in small, permanent pools. An additional example is the rapid divergence of Enallagma damselflies, which have added 23 new species from seven lineages in the last 250,000 years (Turgeon et al., 2005). In contrast are lineages such as Ginkgo, which appears to have changed little since the Jurassic (Zhou and Zheng, 2003). ...
... Aeshna interrupta is another good example of a species with widespread geographic variation . Genetic work may also help determine the relationships among Palaearctic and Nearctic species, as was done with the separation of the Nearctic Enallagma annexum from the Palaeartic E. cyathigerum (Charpentier) (Turgeon et al. 2005). ...
Since Corbet’s thorough 1979 overview of Canadian Odonata, hundreds of regional works on taxonomy, faunistics, distribution, life history, ecology and behaviour have been written. Canada records 214 species of Odonata, an increase of 20 since the 1979 assessment. Estimates of unrecorded species are small; this reflects the well-known nature of the fauna. A major impetus for surveys and analyses of the status of species is the work of the Committee on the Status of Endangered Wildlife in Canada which provides a scientifically sound classification of wildlife species potentially at risk. As of 2017, six species have been designated “Endangered” and two “Special Concern” (only five of which are officially listed under the Federal Species at Risk Act (SARA)). The Order provides a good example of molecular barcoding effort in insects, as many well-accepted morphological species in Canada have been barcoded to some degree. However, more barcoding of accurately identified specimens of many species is still required, especially in most of the larger families, which have less than 70% of their species barcoded. Corbet noted that the larvae of 15 Canadian species were unknown, but almost all larvae are now well, or cursorily, described. Extensive surveys have greatly improved our understanding of species’ geographical distributions, habitat requirements and conservation status but more research is required to better define occurrence, abundance and biological details for almost all species.
... Male claspers are often species- specific in damselflies (Kennedy, 1922), and are known to be a reproductive isolating mechanism (e.g. Turgeon et al., 2005;Barnard et al., 2017). Changes in clasper morphology make it difficult if not impossible for heterospecific males to form tandems, regardless of visual signals. ...
Differences in sexual signalling may initiate speciation by limiting gene flow among diverging populations. The damselfly Megaloprepus caerulatus exhibits two, visually obvious ‘wing types’ across its range. Males from one subspecies have sexually dimorphic, white-banded wings whereas males from the other subspecies lack the sex-specific white wing band. Using mitochondrial (cytochrome c subunit I and 16S) and nuclear (H3) markers, and measures of body size, wing ratio and secondary genitalia, we identified distinct genetic and morphological clades from Mexico to Panama; absence of a wing band was ancestral. To determine if relative reflectance properties of male and female wing tips cue sexual and competitor identity, as they do for wing dimorphic males, we noted reactions of males lacking wing bands to conspecifics with manipulated wings. Isolation by distance explained only 18% of the molecular variation among clades. Relative to wing dimorphic demes, wing monomorphic populations showed lower adult density, lower resource defence and fewer male–male interactions, suggesting lower sexual selection on males. However, not all were less sexually dimorphic in body size. Males lacking wing bands reacted to conspecifics with manipulated wings in ways suggesting that signals for potential mates and competitors do not differ across wing types, a conclusion that awaits more data. Wing mono- and dimorphic demes in Megaloprepus occur allopatrically over relatively short distances and may be isolated via secondary genitalia or unknown physiological constraints.
... Present patterns of biodiversity distribution are determined by both contemporary climate and historical events (Hawkins et al. 2003;Lei et al. 2015). Notably, since speciation and extinction could be shaped by glacial-interglacial climate change, it could directly affect the phylogenetic structure of present communities (Jansson 2003;Price et al. 2000;Turgeon et al. 2005). Regions with stable climate would preserve paleoendemics and have divergent gene pools, which would favour the evolution of neoendemics (Jansson 2003). ...
University campus is an important component of urban landscapes for biodiversity conservation. However, to our knowledge no study has quantitatively assessed the diversity and structure of bird communities in Chinese university campuses, especially from phylogenetic and functional perspectives. Here, for the first time we linked species richness, phylogenetic structure and body mass structure of campus bird communities with contemporary climate, glacial-interglacial climate change, altitudinal range, population density around campus, area and age of campus to test their associations. We found 393 bird species in 38 university campuses (29% of all Chinese bird species, two species are endangered, four species are vulnerable, and 33 species are near threatened). The variables significantly correlated with campus bird species richness, phylogenetic structure and body mass structure were altitudinal range and mean annual precipitation, glacial-interglacial anomaly in temperature, and altitudinal range, respectively. In particular, there were more species in steeper and wetter campuses, more young species clustered in campuses with stable glacial-interglacial climate, and more species with smaller body size in steeper campuses. Our study highlights the importance of considering both phylogenetic and functional information for biodiversity conservation in urban ecosystems.
... In such a case, speciation in one region may concurrently increase species pool richness and SPFD ( Fig. 1 blue line). On the other hand, speciation is often allopatric with little niche differentiation (McPeek 1998, Turgeon et al. 2005. In this case, speciation may increase species pool richness but the influence on SPFD would depend on the degree of niche differentiation among sister species and may not increase SPFD ( Speciation may be especially likely to create differences in SPFD among regions if one region undergoes an adaptive radiation (McPeek and Brown 2000). ...
Despite decades of research on the species-pool concept and the recent explosion of interest in trait-based frameworks in ecology and biogeography, surprisingly little is known about how spatial and temporal changes in species-pool functional diversity (SPFD) influence biodiversity and the processes underlying community assembly. Current trait-based frameworks focus primarily on community assembly from a static regional species pool, without considering how spatial or temporal variation in SPFD alters the relative importance of deterministic and stochastic assembly processes. Likewise, species-pool concepts primarily focus on how the number of species in the species-pool influences local biodiversity. However, species pools with similar richness can vary substantially in functional-trait diversity, which can strongly influence community assembly and biodiversity responses to environmental change. Here we integrate recent advances in community ecology, trait-based ecology, and biogeography to provide a more comprehensive framework that explicitly considers how variation in SPFD - among regions and within regions through time - influences the relative importance of community assembly processes and patterns of biodiversity. First, we provide a brief overview of the primary ecological and evolutionary processes that create differences in SPFD among regions and within regions through time. We then illustrate how SPFD may influence fundamental processes of local community assembly (dispersal, ecological drift, niche selection). Higher SPFD may increase the relative importance of deterministic community assembly when greater functional diversity in the species pool increases niche selection across environmental gradients. In contrast, lower SPFD may increase the relative importance of stochastic community assembly when high functional redundancy in the species pool increases the influence of dispersal history or ecological drift. Next, we outline experimental and observational approaches for testing the influence of SPFD on assembly processes and biodiversity. Finally, we highlight applications of this framework for restoration and conservation. This species-pool functional diversity framework has the potential to advance our understanding of how local- and regional-scale processes jointly influence patterns of biodiversity across biogeographic regions, changes in biodiversity within regions over time, and restoration outcomes and conservation efforts in ecosystems altered by environmental change. This article is protected by copyright. All rights reserved.
... Climatic oscillations during the Quaternary shaped the biodiversity of Europe by forcing species to move along altitudinal and latitudinal gradients, driving diversification and genetic differentiation of these species in glacial refugia (Hewitt, 2004). Although climatic changes during the Pleistocene have been shown to decrease speciation rates in some organisms (Turgeon, Stoks, Thum, Brown, & Mcpeek, 2005), the effect of glaciations in isolating populations within species had a positive effect on speciation rates in many groups of organisms (e.g., Bennett, 2004;Good-Avila, Souza, Gaut, & Eguiarte, 2006;Zink, Klicka, & Barber, 2004). Alternating cycles of population fragmentation and expansion during the Pleistocene provided opportunities for Figure 2, where clade A contains only C. lucennoiberica samples, clade B gathers C. lucennoiberica plus hybrid individuals with haplotypes H4 and H7, and clade C includes a C. furva individual plus a hybrid individual with haplotype H3. ...
Gene flow among incipient species can act as a creative or destructive force in the speciation process, generating variation on which natural selection can act while, potentially, undermining population divergence. The flowering plant genus Carex exhibits a rapid and relatively recent radiation with many species limits still unclear. This is the case with the Iberian Peninsula (Spain and Portugal) endemic C. lucennoiberica, which lay unrecognized within Carex furva until its recent description as a new species. In this study, we test how these species were impacted by interspecific gene flow during speciation. We sampled the full range of distribution of C. furva (15 individuals sampled) and C. lucennoiberica (88 individuals), sequenced two cpDNA regions (atpI-atpH, psbA-trnH) and performed genomic sequencing of 45,100 SNPs using restriction-site associated DNA sequencing (RAD-seq). We utilized a set of partitioned D-statistic tests and demographic analyses to study the degree and direction of introgression. Additionally, we modeled species distributions to reconstruct changes in range distribution during glacial and interglatial periods. Plastid, nuclear, and morphological data strongly support divergence between species with subsequent gene flow. Combined with species distribution modeling, these data support a scenario of allopatry leading to species divergence, followed by secondary contact and gene flow due to long-distance dispersal or range expansions and contractions in response to Quaternary glacial cycles. We conclude that this is a case of allopatric speciation despite historical secondary contacts which could have temporally influenced the speciation process, contributing to the knowledge of forces that are driving or counteracting speciation. This article is protected by copyright. All rights reserved.
... supporting our spatial scale prediction. The Mid Atlantic also appears to be at a crossroad, with Enallagma and other odonates following complex evolutionary and colonization pathways (Turgeon et al. 2005, Corser et al. 2014). This region also includes several Enallagma species confined to the Atlantic coastal plain, potentially creating turnover between coastal and non-coastal localities. ...
An information tradeoff exists between systematic presence/absence surveys and purely opportunistic (presence-only) records for investigating the geography of community structure. Opportunistic species occurrence data may be of relatively limited quality, but typically involves numerous observations and species. Given the quality-quantity tradeoff, what can opportunistic data reveal about spatial patterns in community structure? Here we explore opportunistic data in describing geographic patterns of species composition, using over 4,600 occurrence records of Enallagma damselflies in the United States. We tested phylogenetic scale (genus level, Enallagma major clades, Enallagma subclades) and spatial extent (U.S. vs. watershed regions), hypothesizing that nonrandom structure is more likely at larger spatial extents. We also used three sets of systematic presence/absence surveys as a benchmark for validating opportunistic presence-only records. Null model analysis of matrix coherence and species replacements showed many cases of nonrandom structure and widespread species turnover. This outcome was repeated across spatial and environmental gradients and community composition scenarios. Turnover dominated across the U.S. and two watersheds spanning biogeographic boundaries, but random assemblages were prevalent in a third watershed with limited longitudinal extent. Turnover also pervaded each level of phylogeny. Opportunistic presence-only datasets showed identical patterns as systematic presence/absence datasets. These results indicate that extensive opportunistic data can be used to detect species turnover, especially at geographic scales where range margins are crossed. This article is protected by copyright. All rights reserved.
... Local biodiversity is strongly influenced by speciation and extinction caused by ecological and non-ecological factors. Many studies have shown that climate patterns also have an impact on radiation and the diversification of species [14]. Some studies have investigated the habitat, distribution, abundance, and morphology of the damselfly in Bogani Nani Wartabone National Park (BNWB-NP) [15], but there has been no research on their genetic aspects to date, especially in P. pilidorsum. ...
Pseudagrion pilidorsum is 1 of over 140 species of Pseudagrion (in the family Coenagrionidae), the largest genus of damselfly. This species exhibits dimorphism due to the different body colorations of males and females, making them difficult to distinguish from other congeneric species. This study analyzed the cytochrome C oxidase subunit I (COI) gene sequence of P. pilidorsum found in Bogani Nani Wartabone National Park (North Sulawesi) and compared it with other sequences of P. pilidorsum from distinct geographical locations in Asia. The COI gene for the Sulawesi specimen was amplified using the universal primer pair LCO1490 and HCO2198. A sequence homology search was conducted through BLAST. Multiple sequence alignment was executed using CLUSTAL O (1.2.1). A phylogenetic tree was constructed using the Neighbor-Joining method, and genetic distance was calculated using the Kimura 2-parameter. The COI gene sequence of the Sulawesi specimen lies in the range of 83.99-89.10% with other P. pilidorsum deposited at
GenBank, namely KF369526 (Sarawak specimen), AB708543, AB708544, and AB708545 (Japan specimens). The genetic distance falls in the range of 0.146-0.149 between the Sarawak specimen and the Japan specimen; 0.122-0.125 between the Sulawesi and Japan specimens; and 0.185 between the Sulawesi specimen and the Sarawak specimen. It can thus be inferred that the Sarawak and Japan specimens may not belong to the same species; the Sulawesi and Japan specimens may not belong to the same species; and the Sarawak specimen and Sulawesi specimens might be placed in different genera.
... clade (Fig. 12), with high to medium supports by three methods, although there is no support for the deeper branches (Fig. 12). This may be explained by the adaptive radiation of speciation within a short period (Turgeon 2005), or it may need to be better resolved using more conservative nuclear markers in the future (e.g. 28S rDNA in Shih et al. 2013Shih et al. , 2015Shih 2015;histone 3 in Yeo et al. 2007). ...
Freshwater crabs of the genus Sinopotamon Bott, 1967 (family Potamidae) are widely distributed along the Yangtze River (= Chang Jiang) drainage and are endemic to China. Two distinct clades can be distinguished within Sinopotamon s. lato. on the basis of morphological and molecular data. One clade corresponds to Sinopotamon s. str., with the type species Potamon (Potamon) davidi Rathbun, 1904, and 11 other species, all which occur in the Sichuan Basin (including Sichuan Province and Chongqing City) and reach the border areas of adjacent Shaanxi, Hubei, and Guizhou provinces. A new genus, Longpotamon gen. nov., is proposed for the second clade, with Sinopotamon exiguum Dai, 1997, designated as the type species. Sinopotamon s. str. can be distinguished from Longpotamon gen. nov. by the shape of the male telson and by characters of the male first gonopod and the female vulvae. These differences are supported by the mitochondrial 16S rDNA and cytochrome oxidase subunit I (COI) genetic data. Longpotamon gen. nov. is the largest clade, with 73 known species and a wide distribution along the Yangtze River drainage extending north to the Yellow River drainage and south to the eastern side of Wuyishan Range. The two genera overlap in the Sichuan Basin and the adjacent provinces.
... 1). Phylogram/Cladogram was earlier generated by [19] on the basis of geometric morphometrics data to determined differences/similarities among taxa and suggested as a novel method to visualize morphological variations in a type of profile/shape [20] . was constructed phylogram/cladogram on basis of Color variants among the species of damselflies genus Enallagma. ...
Current study was conducted on Gomphidae dragonflies in Hazara region of Pakistan. A total 125 specimens were collected and identified in to 8 species and 6 genera. Five morphometric parameters were based to evaluate the variations and similarities among species. The results were obtained using the principle component analysis. Components PC1 and PC2 were observed positive correlated with all variables. Highest Euclidean distance was observed (5.14) between Platygomphus dolabratus and Anormogomphus kiritschenkoi, while the lowest Euclidean distance was found (0.27) between Onychogomphus biforceps and O. bistrigatus. Cladogram was showed two groups I and II and result of Line plot highly support the cladogram. Case wise variability showed 6 (75%) and 2 (25%) species were conspired in the same region between (0 to +2.5) and (0 to-2.5) respectively. The component/factors variability plot was observed the cumulative share for PC1 (60.60%) and PC2 (36.82%) respectively. Morphometry and its findings are very important for identification purposes.
... Dumont et al. 2010). Aber auch Untersuchungen zur Klärung glazialer Radiationen und phylo geografischer Fragen gibt es (z.B.Turgeon & Mcpeek 2002;Turgeon et al. 2005). Untersuchungen an Nehalennia speciosa erbrachten eine äußerst geringe genetische Differenzierung zwischen verschiedenen europäischenPopulationen (Bernard & Schmitt 2010). ...
Western Palaearctic distribution patterns of dragonflies – evidence of glacial faunal relicts? The examples of Sympecma paedisca and Somatochlora metallica (Odonata: Lestidae, Corduliidae) – The western range margins of the transpalaearctic species, S. paedisca and S. metallica, have a particular shape and populations disjunct from the main range. Current theory suggests that these distribution patterns arose from a recolonisation after the Pleistocene. In this study I propose that these patterns are better explained by processes that happened during, rather than after, the Pleistocene. Specifically, S. paedisca probably recolonised the western range during the warmer interglacial periods. Somatochlora metallica probably is a eurythermic glacial species whose historic Doggerland range was divided during the last glacial period in a southern and a northern part. The testing of these hypotheses will be possible by genetic studies. The colonisation hypotheses of the two species are supported by a number of shared ecological characters: ● They have a transpalaearctic distribution with clearly disjunct populations at the range margins. ● They are cold stenothermic, or eurythermic. None are habitat specialists in their main range but become habitat specialists towards the range margins. ● These species are also able to survive under current, often anthropogenical, large-scale landscape changes and to colonise new habitats within their range. ● The species have reduced dispersal ability on their western palaearctic range margins, though the reasons are unknown. Zusammenfassung Sympecma paedisca und Somatochlora metallica sind transpaläarktisch verbreitet und ha-ben markante, disjunkte westpaläarktische Arealränder. Im Vergleich zu bisherigen Erklä-rungsversuchen postpleistozäner Wiederbesiedlungsszenarien in der Westpaläarktis sind diese Teilareale schlüssiger mit kaltzeitlichen Geschehnissen in Verbindung zu bringen.
... In a series of detailed studies as part of a global investigation of the regional species richness of Nearctic Enallagma Charpentier, 1840 species (Turgeon & McPeek 2002), male appendages of six closely related species were analysed using high-resolution micro-CT scanning (McPeek et al. 2011). This high-precision technology was required because Enallagma is one of the most species-rich genera of Zygoptera, with 46 currently species (Schorr & Paulson 2014) that share very similar morphology, with some species able to hybridise (Turgeon et al. 2005). The taxonomy of this genus has been revised (May 2002), and a recently proposed phylogeny distinguishes six separate clades (McPeek et al. 2008). ...
The taxonomy of the damselfly genus Xanthocnemis is revised, with particular focus on populations inhabiting the North Island of New Zealand. Earlier studies revealed two species: X. sobrina, restricted to cool, shaded streams in kauri forests and other forested areas, and X. zealandica, a common species throughout New Zealand except the Chatham and subantarctic islands. A field study encompassing aquatic habitats throughout the whole North Island was carried out to establish the relationship between morphological variation (body size and various morphological traits over the entire body) observed by previous researchers with ecological conditions and/or geographical location. The main aim was to propose reliable diagnostic features that could be used in future studies. Morphological and molecular variation was assessed. Morphological examination included assigning landmarks for all body parts corresponding to the external morphological features that are usually used in Odonata taxonomy. Molecular analysis targeted fragments of the 28S and 16S rRNA genes. Congruence was sought between both types of data, statistical support for two morphological types previously described as different species and a maximum likelihood phylogenetic tree in conjunction with a pairwise genetic distance matrix constructed from the DNA sequences obtained from the sampled specimens. Geometric morphometrics revealed statistically significant differentiation between specimens identified as X. zealandica and X. sobrina for four traits: (1) dorsal view of the head for both sexes as well as male appendages from (2) dorsal, (3) ventral and (4) lateral views. Wings appeared different when analysed for males only. Molecular analysis, however, grouped all specimens into a single undifferentiated cluster with very low mean pairwise distance (<0.01) between them showing almost no variation at the molecular level among the sampled populations on the North Island. Therefore, an additional analysis of the mitochondrial cytochrome c-oxidase I gene was carried out comparing randomly selected North Island specimens to Xanthocnemis specimens targeted in other molecular studies (Nolan et al. 2007, Amaya-Perilla et al. 2014). The analysis of the COI gene confirmed that all North and South Island isolates of Xanthocnemis cluster together in a well-supported clade with pairwise identity >96% and ~93% pairwise identity with X. tuanuii sequences obtained from the Chatham Island specimens. A careful investigation of the thin plate spline deformations generated for the geometric morphometric landmarks showed that the significant variations in the appendages of the Xanthocnemis specimens appeared to be the result of size, rather than shape, differences. Therefore, X. sobrina is proposed as a synonym of X. zealandica. Recently Amaya-Perilla et al. (2014) synonymised X. sinclairi with X. zealandica and confirmed the status of the Chatham Island X. tuanuii as a distinct species. It is therefore proposed that the genus Xanthocnemis consists of two species only: zealandica occurring all over the North, South and Stewart Islands, and tuanuii, endemic to Chatham and Pitt islands. Considering several statistical tests involving body measurements and ecological variables recorded during the field study, as well as various discussion points from similar studies of other species of Odonata, two alternative hypotheses are proposed for future testing. The first hypothesis synonymises X. sobrina with X. zealandica and suggests a possible explanation for the evolution of the two morphological traits that have previously been considered diagnostic for these species. The second hypothesis suggests that as typical X. sobrina were not sampled during this study this could represent a species that is now extinct, unless future studies prove it otherwise.
... While forty Enallagma species occur in the New World (mostly North America), only four inhabit the Old World. Morphological and genetic studies revealed that Enallagma consists of two subgenera (Brown et al. 2000, May 2002, Turgeon & McPeek 2002, Turgeon et al. 2005. The subgenus Chromatallagma May, 2002 includes seventeen species with a mostly southern Nearctic distribution. ...
This work is the first detailed and comprehensive overview of the distribution of the dragonflies and damselflies of Europe. It is an important milestone for professionals and amateurs alike. Covers the distribution and habitat selection of all 143 European species of dragonflies and damselflies. Gives a complete description of their global and European distribution, illustrated by over 200 distribution maps. Gives for each species information on taxonomy, range, population trends, flights season and habitat. Includes unique photos and flight season diagrams for virtually all European species. Contains extensive background information on taxonomy, conservation, and for each country an overview of the history of odonatological studies. The book is the result of a co-operation of over 50 European dragonfly experts who over the past decade compiled all records of dragonflies and damselflies, from the Azores to the Ural and from the North Cape to Lampedusa. These records were gathered by thousands of volunteers from across Europe. This endeavour was coordinated by Jean- Pierre Boudot (Société Française d’Odonatologie) and Vincent Kalkman (European Invertebrate Survey – Netherlands/Naturalis Biodiversity Centre).
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... They have complex mating systems and unique copulatory structures (Schmidt 1915;carle 1982a;Pfau 1971Pfau , 2011, and have been the subjects of important studies of behavior and ecology (corBet 1999). They are cosmopolitan, yet many subgroups are geographically or environmentally restricted, making them useful study organisms for biogeographers (e.g., tillyard 1917;Wat-Son 1977;carle 1982aturgeon et al. 2005) including the identification of areas of endemism (e.g., tillyard 1917;mitra et al. 2010;clauSnitZer et al. 2012). ...
A phylogeny of Anisoptera employing 510 representatives of 184 genera (of ca. 380) in 11 families is presented based on an analysis of over 10,000 nucleotides from portions of the large and small subunit nuclear and mitochondrial ribosomal RNA's, the mitochondrial protein coding genes COI and COII, and portions of the nuclear protein coding genes EF-1a and Histone H3. Ribosomal sequences were structurally aligned and sequences carefully checked to eliminate alignment errors, contamination, misidentification and paralogous gene amplicons. Both the RAxML and Bayesian topology based on consolidation of data at the generic level is ((Austropetaliidae, Aeshnidae), ((Gomphidae, Petaluridae), ((Chlorogomphidae, (Neopetaliidae, Cordulegastridae)), (Synthemistidae, (Macromiidae, (Corduliidae, Libellulidae)))))). As the positions of Petaluridae, Chlorogomphidae, Neopetaliidae, and Cordulegastridae are weakly supported, possible alternative hypotheses are discussed. New taxonomic groups established include: in Gomphidae, Stylogomphini trib.n. and Davidioidini trib.n., and in Libellulidae, Dythemistinae subfam.n. including Dythemistini trib.n., Pachydiplactini trib.n. and Elgini trib.n. New taxonomic arrangements include: placement of Hemigomphini in Ictinogomphinae, and provisional expansion of Synthemistidae to include Gomphomacromiinae and a number of genera formerly placed in several small subfamilies of Corduliidae. Idomacromiinae is placed sister to remaining Synthemistidae s.l. based on molecular analysis of Idomacromia Karsch and Oxygastra Selys. Hemicorduliidae and Macrodiplactidae are nested well within Corduliidae and Libellulidae, respectively, and therefore are not accorded family rank. Eleven monophyletic subdivisions of Libellulidae are tentatively recognized as subfamilies: Dythemistinae subfam.n.; Sympetrinae (including Leucorrhiniini and Rhyothemistini); Macrodiplactinae; Brachydiplactinae; Tetrathemistinae; Trameinae; Zyxommatinae; Palpopleurinae; Diastatopidinae; Pantalinae (including Trithemistini and Onychothemistini); and Libellulinae. Zygonychini is paraphyletic to and therefore included within Onychothemistini.
... Phylogeny-based analysis of diversification provides some limited evidence for increasing speciation through time (e.g. Barraclough and Vogler 2002;Linder et al. 2003;Turgeon et al. 2005), but again, a scenario of rapid radiation followed by a decline in speciation rate over time appears to be more common (Harmon et al. 2003;Shaw et al. 2003;Kadereit et al. 2004;Machordom and Macpherson 2004;Morrison et al. 2004;Williams and Reid 2004;Xiang et al. 2005;Kozak et al. 2006;Weir 2006;Phillimore and Price 2008;Scantlebury 2013). This pattern could be linked to a density-dependent model of ecological opportunity and/or reflect punctual mass extinctions (e.g. ...
Analysing extinctions within a phylogenetic framework may seem counter-intuitive because extinction is a priori a non-heritable trait. However, extinction risk is correlated with other traits, such as body size, that show a strong phylogenetic signal. Further, there has been much effort in identifying key traits important for diversification, and recent evidence has demonstrated that the processes of speciation and extinction may be inextricably linked. A phylogenetic approach also allows us to quantify the impact of extinctions, for example, as the loss of branches from the tree-of-life. Early work suggested that extinctions might result in little loss of evolutionary history, but subsequent studies indicated that nonrandom extinctions might prune more of the evolutionary tree. Loss of phylogenetic diversity might have ecosystem consequence because functional differences between species tend to be correlated with the evolutionary distances between them. Here we explore how extinction prunes the tree-of-life. Our review indicates that the loss of evolutionary history under non-random extinction (the emerging pattern in extinction biology) might be less pronounced than some previous studies have suggested. However, the loss of functional diversity might still be large, depending on
the evolutionary model of trait change. Under a punctuated model of evolution, in which trait differences accrue in bursts at speciation, the number of branches lost is more important than their summed lengths. We suggest that evolutionary models need to be incorporated more explicitly into measures of phylogenetic diversity if we are to use phylogeny as a proxy for functional diversity.
... Both phenomena impacted species distributions [72]. These migrations brought species in contact and favored hybridization and the formation of polyploid species (e.g., [73]), two factors that appear to have played an important role in the rapid diversification of subg. Vetrix. ...
Salix L. is the largest genus in the family Salicaceae (450 species). Several classifications have been published, but taxonomic subdivision has been under continuous revision. Our goal is to establish the phylogenetic structure of the genus using molecular data on all American willows, using three DNA markers. This complete phylogeny of American willows allows us to propose a biogeographic framework for the evolution of the genus. Material was obtained for the 122 native and introduced willow species of America. Sequences were obtained from the ITS (ribosomal nuclear DNA) and two plastid regions, matK and rbcL. Phylogenetic analyses (parsimony, maximum likelihood, Bayesian inference) were performed on the data. Geographic distribution was mapped onto the tree. The species tree provides strong support for a division of the genus into two subgenera, Salix and Vetrix. Subgenus Salix comprises temperate species from the Americas and Asia, and their disjunction may result from Tertiary events. Subgenus Vetrix is composed of boreo-arctic species of the Northern Hemisphere and their radiation may coincide with the Quaternary glaciations. Sixteen species have ambiguous positions; genetic diversity is lower in subg. Vetrix. A molecular phylogeny of all species of American willows has been inferred. It needs to be tested and further resolved using other molecular data. Nonetheless, the genus clearly has two clades that have distinct biogeographic patterns.
... En lo que respecta a cambios nomenclaturales, el taxón que para México y Norteamérica era ubicado en listas anteriores como Enallagma cyathigerum (Charpentier, 1840) corresponde en realidad a E. annexum (Hagen, 1861), según estudios moleculares recientes (Turgeon et al., 2005); E. cyathigerum tiene una distribución euroasiática. Por otro lado, también ha quedado documentado que las poblaciones de América continental que se ubicaban anteriormente como Dythemis multipunctata, Kirby, 1894 corresponden en realidad a Dythemis nigra Martin, 1897; D. multipunctata es endémica de la isla de San Vicente en las Antillas Menores (Meurgey y Poiron, 2011). ...
Se presenta un capítulo actualizado sobre Odonata de México. Desde la última actualización en 2006, se describieron 5 especies nuevas, se adicionaron 11 registros nuevos y se describieron 14 especies en estado larval. Por tanto, la lista mexicana que aquí se presenta está constituida por un total de 355 especies. Se incluyen comentarios sobre endemismo, especies amenazadas y/o en riesgo.
... Eventually, our simulations show high variability in and through time and among replicates, in agreement with the analysis of real phylogenies (e.g., Purvis 1995;Pybus and Harvey 2000;Barraclough and Vogler 2002;Linder et al. 2003;Turgeon et al. 2005, and online Appendix 9 available as Supplementary Material on Dryad at http://dx.doi.org/10.5061/dryad.3bp51). This variability originates from the intrinsic stochasticity of the diversification process, and is amplified by small species numbers. ...
Whether biotic or abiotic factors are the dominant drivers of clade diversification is a long-standing question in evolutionary biology. The ubiquitous patterns of phylogenetic imbalance and branching slowdown have been taken as supporting the role of ecological niche filling and spatial heterogeneity in ecological features, and thus of biotic processes, in diversification. However, a proper theoretical assessment of the relative roles of biotic and abiotic factors in macroevolution requires models that integrate both types of factors, and such models have been lacking. In this study, we use an individual-based model to investigate the temporal patterns of diversification driven by ecological speciation in a stochastically fluctuating geographic landscape. The model generates phylogenies whose shape evolves as the clade ages. Stabilization of tree shape often occurs after ecological saturation, revealing species turnover caused by competition and demographic stochasticity. In the initial phase of diversification (allopatric radiation into an empty landscape), trees tend to be unbalanced and branching slows down. As diversification proceeds further due to landscape dynamics, balance and branching tempo may increase and become positive. Three main conclusions follow. First, the phylogenies of ecologically saturated clades do not always exhibit branching slowdown. Branching slowdown requires that competition be wide or heterogeneous across the landscape, or that the characteristics of landscape dynamics vary geographically. Conversely, branching acceleration is predicted under narrow competition or frequent local catastrophes. Second, ecological heterogeneity does not necessarily cause phylogenies to be unbalanced - short time in geographical isolation or frequent local catastrophes may lead to balanced trees despite spatial heterogeneity. Conversely, unbalanced trees can emerge without spatial heterogeneity, notably if competition is wide. Third, short isolation time causes a radically different and quite robust pattern of phylogenies that are balanced and yet exhibit branching slowdown. In conclusion, biotic factors have a strong and diverse influence on the shape of phylogenies of ecologically saturating clades and create the evolutionary template in which branching slowdown and tree imbalance may occur. However, the contingency of landscape dynamics and resource distribution can cause wide variation in branching tempo and tree balance. Finally, considerable variation in tree shape among simulation replicates calls for caution when interpreting variation in the shape of real phylogenies.
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... Biogeographical and other research is enhanced because large collections of accurately identified material from many regions of the world are available. There is a wealth of cladistics work on the Odonata that should have been explored and summarized in at least one chapterfrom biogeographical hypotheses of Quaternary radiations (Turgeon et al. 2005) and the effects of Gondwana's breakup (Carle 1995) to studies of evolutionary rates (Hasegawa and Kasuya 2006); from the adaptive radiation of the endemic Hawai-ian Megalagrion (Jordan et al. 2003) to more general investigations of taxon evolution (Ware et al. 2007) and the evolution of structure (Bybee et al. 2008). ...
... Song et al. (2006) have shown that geographic differentiation is often underestimated. Nonetheless, in Noctuidae, speciation was much slower than in the Enallagma damselflies (Odonata) in the northern Holarctic caused by climate fluctuations in the Quaternary (Turgeon et al., 2005). The " biological species concept " developed by Mayr ...
In the Noctuidae, the owlet moths, the internal genitalia, i.e. the aedeagus and vosica (penis) in the males, and the bursa copulatrix in the females, together form a lock-and-key mechanism (LKM). The species-specific structures have their counterparts in the opposite sex. The internal LKM constitutes a specific reproductive isolation mechanism (lock-and-key hypothesis), which seem to be the rule in the ditrysian Lepidoptera, and also occurs in the Carabidae (Coleoptera) and some other insects. In contrast, the external genitalia rarely have species-specific counterparts in the sexes. Several results indicate the presence of LKMs: In the Noctuidae, (1) heterospecific differences in the male vesica may prevent sperm transfer or lead to mechanical failure during copulation, (2) the more complicated the specific genitalia structures, the more aberrations may occur even in conspecific copulations, and (3) in many species pairs and groups, and in one large genus, Apamea, the structures in the opposite sexes show a strictly specific correspondence, but, (4) when there is precopulatory isolation due to differences in pheromone production or perception, the internal genitalia may be identical. Conversely, in the Colias butterflies (Pieridae). (5) frequent huterospecific hybridization is associated with the similarity of the internal genitalia. The LKMs seem to protect genomes against alien genes, supposedly selected for because of the lower fitness of specimens with an imprecise LKM and/or inferiority of hybrids. In the literature, the diversity of the noctuid genitalia has been ascribed to sexual selection, because the females were classified as polyandrous. Most species produce the main part of their eggs monandrously, and remate, if at all, in their old age, and are thus successively monandrous and polyandrous. The allopatric divergence in the structure of the internal genitalia of 39 Holarctic pairs of sister species of Noctuidae is suggested to be due to genetic drift. The insecure function of the female pheromones and external genitalia of males are illustrated with the aid of original photographs.
Heterospecific interactions are an important phenomenon of animal epigamic behaviour; however, they remain understudied within important groups, such as insects. Dragonflies are an ideal group for research on interspecific mating and possible hybridisation as they are easily identifiable, large insects, with a conspicuous mating process, often striking territorial behaviour and several mating systems.
Using the genus Sympetrum as the model group, we examined heterospecific mating at three different levels. In the field, we identified whether species identity, time and weather affected heterospecific mating frequency. One important part of heterospecific mating is whether the process is completed. For dragonflies, this means that flying in tandem is followed by successful copulation, gamete fusion and oviposition (which comprise mating completeness). In a mesocosm experiment, we determined mating completeness (tandems, copulation, oviposition) of hetero‐ and homospecific pairs and the possible role of species density in heterospecific mating. In the laboratory, we compared the viability of the offspring from heterospecific pairs with different epigamous behaviour.
We found heterospecific mating to be a relatively common phenomenon unaffected by environmental variables, that was primarily influenced by species identity, temporal distribution and abundance of dragonfly species. Consequently, the presence of counterparts of other species is the main predictor of the frequency of heterospecific mating.
The probability of completed epigamic behaviour (copulation and subsequent oviposition) connected with gamete fusion is lower in heterospecific mating. Generally, based on our results we can assume that successful heterospecific mating (leading to gamete fusion) occurs in closely related species (e.g., Sympetrum striolatum and Sympetrum vulgatum ). However, as pre‐copulatory barriers are not strongly developed in some dragonfly groups, less closely related species (e.g., Sympetrum sanguineum and S. striolatum ) also may mate. This phenomenon requires further study as it may present a threat to the survival of some species in the context of changing environmental conditions, including climate change.
Time-calibrated phylogenies of extant species (“extant timetrees”) are widely used to estimate historical speciation and extinction rates by fitting stochastic birth-death models.¹ These approaches have long been controversial, as many phylogenetic studies report zero extinction in many taxa, contradicting the high extinction rates seen in the fossil record and the fact that the majority of species ever to have existed are now extinct.2, 3, 4, 5, 6, 7, 8, 9 To date, the causes of this discrepancy remain unresolved. Here, we provide a novel and simple explanation for these “zero-inflated” extinction estimates, based on the recent discovery that there exist many alternative “congruent” diversification scenarios that cannot be distinguished based solely on extant timetrees.¹⁰ Due to such congruencies, estimation methods tend to converge to some scenario congruent to (i.e., statistically indistinguishable from) the true diversification scenario, but not necessarily to the true diversification scenario itself. This congruent scenario may exhibit negative extinction rates, a biologically meaningless but mathematically feasible situation, in which case estimators will tend to stick to the boundary of zero extinction. Based on this explanation, we make multiple testable predictions, which we confirm using analyses of simulated trees and 121 empirical trees. In contrast to other proposed mechanisms for erroneous extinction rate estimates,⁵,11, 12, 13, 14 our proposed mechanism specifically explains the zero inflation of previous extinction rate estimates in the absence of detectable model violations, even for large trees. Not only do our results likely resolve a long-standing mystery in phylogenetics, they demonstrate that model congruencies can have severe consequences in practice.
Background:
The Odonata, dragonflies and damselflies, constitute one of the more charismatic and better-studied orders of insects. The approximately 6,000 extant species on Earth can be variously found on all continents, except Antarctica. A relatively stable taxonomy, a relative ease of species identification and an aquatic immature stage has made the Odonata a taxon of interest in documenting the symptoms of global environmental change, especially at higher latitudes. The Odonata fauna of the north-temperate Canadian province of Quebec includes 150 species, many of which are at the northern limits of their geographic distribution.
New information:
Quebec hosts multiple entomological specimen depositories, including seven publicly-accessible research collections. One of these, the University of Montreal's Ouellet-Robert Entomological Collection, houses an exceptionally large collection of Odonata. An initial specimen data capture project for this collection gathered 31,595 Quebec Odonata occurrence records, but several Quebec species were missing and geographic coverage was biased towards the Montreal region. To complement this dataset, we undertook to digitise the Odonata records of six other public research collections. They are, in order of Quebec Odonata collection size, the Laval University Entomological Collection, McGill University's Lyman Entomological Museum, the Insectarium of Montreal Research Collection, the Quebec Government's Insect Collection, Bishop's University's Insect Collection and the Laurentian Forestry Centre's René-Martineau Insectarium. Of the 40,447 total specimen occurrence records, 36,951 are identified to the species level, including 137 of the 150 species officially-recorded in Quebec and 2 non-nominotypical subspecies. We here summarise the data and highlight the strengths and weaknesses of the datasets. The complete dataset is available with this publication (Suppl. material 1), whereas the specimen data associated with each collection are available as Darwin Core archives at Canadensys.net and will be updated as appropriate.
Opportunities for researchers, teachers, students and citizen scientists to make contributions to our knowledge on the Odonata nymphs of North America are introduced. The main taxonomic needs are rearing and describing the nymphs of 50 species of Anisoptera that are still poorly known or unknown and using the data to emend the respective identification keys. Fully evaluating nymph characters will advance attempts at integrating morphological and molecular approaches to species distinctions and phylogeny. Very few of the 330 North American Anisoptera species (~6%) have been reared through all stages from egg to full-grown nymph, resulting in an inability to identify most early instars. The structure and function of various types of nymphal setae and their role in detecting stimuli and affording camouflage constitute an exciting field for research opportunities. Growth rate, life history and habitat of most species are under-studied. Utilization of Anisoptera nymphs in biomonitoring and conservation efforts shows that Odonata provide useful regional tools but the field has not been fully researched and the value of Odonata in such pursuits is undoubtedly underestimated. In summary, data generated by studies in these various subject areas will be useful in evaluating faunal surveys, constructing phylogenetic analyses, furthering education outreach and public awareness, and enhancing species and habitat conservation efforts.
Most species have evolved adaptations to reduce the chances of predation. In many cases adaptations to coexist with one predator generate tradeoffs in the ability to live with other predators. Consequently, the ability to live with one predator may limit the geographic distributions of species, such that adaptive evolution to coexist with novel predators may facilitate range shifts. In a case study with Enallagma damselflies, we used a comparative phylogenetic approach to test the hypothesis that adaptive evolution to live with a novel predator facilitates range size shifts. Our results suggest that the evolution of Enallagma shifting from living in ancestral lakes with fish as top predators, to living in lakes with dragonflies as predators, may have facilitated an increase in their range sizes. This increased range size likely arose because lakes with dragonflies were widespread, but unavailable as a habitat throughout much of the evolutionary history of Enallagma because they were historically maladapted to coexist with dragonfly predators. Additionally, the traits that have evolved as defenses against dragonflies also likely enhanced damselfly dispersal abilities. While many factors underlie the evolutionary history of species ranges, these results suggest a role for the evolution of predator-prey interactions. This article is protected by copyright. All rights reserved.
Reflections on the faunal history of Odonata in Europe during the Weichsel Glacial Stage
(Odonata) — In contrast to other aquatic insect groups, no relevant discussion on the faunal
history of the Odonata during the Ice Age exists. In the present paper I examine previous
hypo theses regarding the postglacial settlement of dragonflies in Europe. I include a short
overview of the processes during the Ice Age. Especially I write about the present state of
knowledge of the climate, countryside and habitats during the Weichsel Glacial Stage. There
are in East Germany extensive findings from about 33,000 years ago. But there is no fossil evidence
of dragon flies from that time. In addition, in the context of present knowledge of the
ecology, mor pho logy, physiology and dispersal of Odonata, I develop a hypothesis regarding the
possible dragon fly fauna of the tundra of that time. It is possible that both coldstenothermic
and eurythermic species belong to this periglacial fauna. I offer further suggestions regarding
the treatment of this question that may contribute to a better understanding of ecological
findings and to the history of dispersion and zoogeography of Palaearctic dragonflies.
Ninety-two species are currently recorded in Oregon. Additional and updated records since Johnson & Valley (2005) are summarized for 28 species and one hybrid with some range maps updated. The current county records and early/late flight dates for all known species in Oregon are presented.
Bringing together the viewpoints of leading ecologists concerned with the processes that generate patterns of diversity, and evolutionary biologists who focus on mechanisms of speciation, this book opens up discussion in order to broaden understanding of how speciation affects patterns of biological diversity, especially the uneven distribution of diversity across time, space and taxa studied by macroecologists. The contributors discuss questions such as: Are species equivalent units, providing meaningful measures of diversity? To what extent do mechanisms of speciation affect the functional nature and distribution of species diversity? How can speciation rates be measured using molecular phylogenies or data from the fossil record? What are the factors that explain variation in rates? Written for graduate students and academic researchers, the book promotes a more complete understanding of the interaction between mechanisms and rates of speciation and these patterns in biological diversity.
Bringing together the viewpoints of leading ecologists concerned with the processes that generate patterns of diversity, and evolutionary biologists who focus on mechanisms of speciation, this book opens up discussion in order to broaden understanding of how speciation affects patterns of biological diversity, especially the uneven distribution of diversity across time, space and taxa studied by macroecologists. The contributors discuss questions such as: Are species equivalent units, providing meaningful measures of diversity? To what extent do mechanisms of speciation affect the functional nature and distribution of species diversity? How can speciation rates be measured using molecular phylogenies or data from the fossil record? What are the factors that explain variation in rates? Written for graduate students and academic researchers, the book promotes a more complete understanding of the interaction between mechanisms and rates of speciation and these patterns in biological diversity.
Reconstructing evolutionary patterns of species and populations provides a framework for asking questions about the impacts of climate change. Here we use a multilocus dataset to estimate gene trees under maximum likelihood and Bayesian models to obtain a robust estimate of relationships for a genus of North American damselflies, Enallagma. Using a relaxed molecular clock, we estimate the divergence times for this group. Furthermore, to account for the fact that gene tree analyses can overestimate ages of population divergences, we use a multi-population coalescent model to gain a more accurate estimate of divergence times. We also infer diversification rates using a method that allows for variation in diversification rate through time and among lineages. Our results reveal a complex evolutionary history of Enallagma, in which divergence events both predate and occur during Pleistocene climate fluctuations. There is also evidence of diversification rate heterogeneity across the tree. These divergence time estimates provide a foundation for addressing the relative significance of historical climatic events in the diversification of this genus.
Copyright © 2015. Published by Elsevier Inc.
George Gaylord Simpson famously postulated that much of life’s diversity originated as adaptive radiations—more or less simulta- neous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad-scale comparative datasets. Here, we use phylogenetic comparative data on body size and shape in a diversity of animal clades to test a key model of adaptive radiation, in which initially rapid morphological evolution is followed by relative stasis. We compared the fit of this model to both single selective peak and random walk models. We found little support for the early-burst model of adaptive radiation, whereas both other models, particularly that of selective peaks, were commonly supported. In addition, we found that the net rate of morphological evolution varied inversely with clade age. The youngest clades appear to evolve most rapidly because long-term change typically does not attain the amount of divergence predicted from rates measured over short time scales. Across our entire analysis, the dominant pattern was one of constraints shaping evolution continually through time rather than rapid evolution followed by stasis. We suggest that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.
Seventeen species of Odonata were collected in 1994-1996 from 21 localities in the Kuril Islands. Mnais pruinosa, Aeshna nigroflava, Cordulia aenea, and Pseudothemis zonata are first records from the archipelago, and the last species represents a significant range extension from Honshu. Enallagma belyshevi is synonymized with E. circulatum, which is considered a valid species rather than a subspecies of E. boreale.
The method of modern analogs and an extensive data base of modern and
fossil pollen data were used to generate a new series of paleovegetation
maps for eastern North America spanning the past 18 ka. The maps
illustrate the continuous nature of climate-induced vegetation change
and the development, after about 10 ka, of modern regional vegetation
patterns. Before the Holocene, vegetation biomes without modern analogs
were widespread in response to climate conditions without modern analogs
and, to a lesser extent, to the rapidity of climate change over the last
glacial-interglacial transition. This geological perspective suggests
that possible future climate changes could force similarly complex
changes in natural vegetation, including the development of biomes
without modern analogs.
The Quaternary was a time of extensive evolution among mammals. Most living species arose at this time, and many of them show adaptations to peculiarly Quaternary environments. The latter include continental northern steppe and tundra, and the formation of lakes and offshore islands. Although some species evolved fixed adaptations to specialist habitats, others developed flexible adaptations enabling them to inhabit broad niches and to survive major environmental changes. Adaptation to short-term (migratory and seasonal) habitat change probably played a part in pre-adapting mammal species to the longer-term cyclical changes of the Quaternary. Fossil evidence indicates that environmental changes of the order of thousands of years have been sufficient to produce subspeciation, but speciation has typically required one hundred thousand to a few hundred thousand years, although there are both shorter and longer exceptions. The persistence of taxa in environments imposing strong selective regimes may have been important in forcing major adaptive change. Individual Milankovitch cycles are not necessarily implicated in this process, but nor did they generally inhibit evolutionary change among mammals: many evolutionary divergences built over multiple climatic cycles. Deduction of speciation timing requires input from fossils and modern phenotypic and breeding data, to complement and constrain mitochondrial DNA coalescence dates which appear commonly to overestimate taxic divergence dates and durations of speciation. Migrational and evolutionary responses to climate change are not mutually exclusive but, on the contrary, may be synergistic. Finally, preliminary analysis suggests that faunal turnover, including an important element of speciation, was elevated in the Quaternary compared with the Neogene, at least in some biomes. Macroevolutionary species selection or sorting has apparently resulted in a modern mammalian fauna enriched with fast-reproducing and/or adaptively generalist species.
We propose a new speciation mechanism for hybridizing populations based on frequency- dependent sexual selection theory. In contrast to previous reinforcement and symmetric speciation models, this model does not require viability selection for male sexual traits, selection against unfit hybrids or disruptive selection for ecological traits. The model assumes that females exhibit mating preferences based on male secondary sexual characters. Both female mating preferences and male secondary sexual traits are independent quantitative genetic traits. Females choose using one of five tactics. All individuals, including the hybrids, have the same ability to survive and reproduce. Two populations that differ only in their average values of female preference and male sexual traits are assumed to come into contact and hybridize. Most cases of the model frequently result in complete prezygotic isolation. The likelihood of speciation decreases with the degree of phenotypic overlap between the two merging popula- tions. However, the probability of speciation is not zero even when the two merging populations are identical.
Lake Victoria harbors a unique species-rich flock of more than 500 endemic hap- lochromine cichlid fishes. The origin, age, and mechanism of diversification of this extraordinary radiation are still debated. Geological evidence suggests that the lake dried out completely about 14,700 years ago. On the basis of phylogenetic analyses of almost 300 DNA sequences of the mitochondrial control region of East African cichlids, we find that the Lake Victoria cichlid flock is derived from the geo- logically older Lake Kivu. We suggest that the two seeding lineages may have already been lake-adapted when they colonized Lake Victoria. A haplotype analysis further shows that the most recent desiccation of Lake Victoria did not lead to a complete extinction of its endemic cichlid fauna and that the major lineage diversification took place about 100,000 years ago.
The vagaries of history lead to the prediction that repeated instances of evolutionary diversification will lead to disparate
outcomes even if starting conditions are similar. We tested this proposition by examining the evolutionary radiation ofAnolis lizards on the four islands of the Greater Antilles. Morphometric analyses indicate that the same set of habitat specialists,
termed ecomorphs, occurs on all four islands. Although these similar assemblages could result from a single evolutionary origin
of each ecomorph, followed by dispersal or vicariance, phylogenetic analysis indicates that the ecomorphs originated independently
on each island. Thus, adaptive radiation in similar environments can overcome historical contingencies to produce strikingly
similar evolutionary outcomes.
Late Pleistocene glaciations have been ascribed a dominant role in sculpting present-day diversity and distributions of North
American vertebrates. Molecular comparisons of recently diverged sister species now permit a test of this assertion. The Late
Pleistocene Origins model predicts a mitochondrial DNA divergence value of less than 0.5 percent for avian sister species
of Late Pleistocene origin. Instead, the average mitochondrial DNA sequence divergence for 35 such songbird species pairs
is 5.1 percent, which exceeds the predicted value by a factor of 10. Molecular data suggest a relatively protracted history
of speciation events among North American songbirds over the past 5 million years.
The mechanisms of macroevolutionary change have long been a contentious issue. Palaeoecological evidence, presented in this book, shows that evolutionary processes visible in ecological time do not build up into macroevolutionary trends, contrary to Darwin's original thesis. The author discusses how climatic oscillations on ice-age time-scales are paced by variations in the Earth's orbit, and have thus been a permanent feature of Earth history. There is, however, little evidence for macroevolutionary change in response to these climatic changes, suggesting that over geological time macroevolution does not occur as a result of accumulated short term processes. These conclusions are used to construct a post-modern evolutionary synthesis in which evolution and ecology play an equal role. Written by a leading palaeoecologist, this book will be of interest to researchers in both ecology and evolutionary biology.
A model of sexual selection that leads to the evolution of exaggerated male display characters that is based on antagonistic coevolution between the sexes is described. The model is motivated by three lines of research: intersexual conflict with respect to mating, sensory exploitation, and the evolution of female resistance, as opposed to preference, for male display traits. The model generates unique predictions that permit its operation to be distinguished from other established models of sexual selection. One striking prediction is that females will frequently win the coevolutionary arms race with males, leaving them encumbered with costly ornaments that have little value except that their absence understimulates females. Examples from the literature suggest that the model may have broad application in nature. The chase-away model is a special case of the more general phenomenon of Interlocus Contest Evolution (ICE).
Behavior can play a mediating role in determining the selective pressures that influence the evolution of morphological structures. To examine this, I quantified patterns of morphological variation among larvae of Enallagma damselfly species (Odonata: Coenagrionidae) that use different behaviors to avoid the major predators found in each of two communities, lakes with and without fish. Specifically, I quantified the sizes and shapes of the abdomens and caudal lamellae (used for swimming) and legs for three species from fishless lakes and six species from lakes with fish. A preliminary cladistic analysis indicates that species within each lake type are not members of a single clade, which supports the conclusions of previous odonate taxonomists. Previous studies have shown that species in fishless lakes are very active, running and swimming frequently and at high rates of speed in the absence of predators, and they avoid their primary predators, large dragonflies, by swimming. These species have the widest abdomens, the largest caudal lamellae relative to overall body size, and the longest legs of the species studied, which should make them powerful swimmers and runners. Furthermore, species in fishless lakes are morphologically very similar to one another and differ greatly from fish-lake species, although each is more closely related to species in fish lakes. In contrast, species from lakes with fish move very slowly and infrequently in the absence of predators and do not attempt to evade attacking predators. However, despite their behavioral similarity, large interspecific variation in morphology exists among the fish-lake species, and the only morphological patterns were differences associated with membership in the two primary clades identified in the cladistic analysis. A modification of Felsenstein's (1985) method of evolutionary contrasts which allows character change to be isolated along single branches is introduced and is used to reconstruct the evolutionary histories of these characters. This analysis suggests that large increases in caudal lamella size, abdominal segment lengths and widths, and leg length accompany speciation events associated with habitat shifts from fish-lakes to fishless lakes. Following habitat shifts selection pressures exerted by dragonfly predation apparently favored swimming as an escape tactic, which mediated selection pressures onto morphologies used in swimming to increase swimming performance; morphological patterns in extant species reflect this adaptation to a new environment. Mechanisms by which behaviorally mediated selection could have accelerated evolutionary dynamics following founder events are discussed.
The concept of species flocks has been central to previous interpretations of patterns and processes of explosive species radiations within several groups of freshwater fishes. Here, molecular phytogenies of species-rich Sebastes rockfishes from the northeastern Pacific Ocean were used to test predictions of null theoretical models that assume random temporal placements of phylogenetic nodes. Similar appraisals were conducted using molecular data previously published for particular cichlid fishes in Africa that epitomize, by virtue of a rapid and recent radiation of species, the traditional concept of an intralacustrine "species flock." As gauged by the magnitudes of genetic divergence in cytochrome b sequences from mitochondrial DNA, as well as in allozymes, most speciation events in the Sebastes complex were far more ancient than those in the cichlids. However, statistical tests of the nodal placements in the Sebastes phylogeny suggest that speciation events in the rockfishes were temporally nonrandom, with significant clustering of cladogenetic events in time. Similar conclusions also apply to an ancient complex of icefishes (within the Notothenioidei) analyzed in the same fashion. Thus, the rockfishes (and icefishes) may be interpreted as ancient species flocks in the marine realm. The analyses exemplified in this report introduce a conceptual and operational approach for extending the concept of species flocks to additional environmental settings and evolutionary timescales.
Previous studies have shown that at least two lineages of Enallagma damselflies (Odonata: Coenagrionidae) shifted from inhabiting lakes with fish as top predators to inhabiting ponds and lakes with large dragonflies as the top predators. In adapting to living with the new predator type, these lineages evolved much greater swimming speeds to avoid attacking dragonflies. In this paper, I test whether biochemical adaptations to fuel swimming arose in concert with previously identified morphological changes that increase swimming speed. I assayed the mass-specific enzyme activities of three enzymes involved in fueling strenuous activity: pyruvate kinase and lactate dehydrogenase (enzymes involved in glycolysis) and arginine kinase (the enzyme that recharges the ATP pool). Enzyme activities were determined for 14 Enallagma species from across the genus. Species that coexist with dragonfly predators had significantly higher mass-specific arginine kinase activities than species that coexist with fish, and the results of evolutionary contrasts analyses indicate that this difference between the two groups is the result of evolutionary change associated with the habitat shifts of lineages from fish lakes to dragonfly lakes. Although significant evolution was documented for lactate dehydrogenase and pyruvate kinase across the genus, evolutionary change in the activities of these enzymes was not consistent with adaptation to coexisting with dragonfly predators. Swimming bouts to avoid dragonfly predators last for only a few seconds, and the action of arginine kinase to phosphorylate ADP to make ATP will extend the duration of maximal exertion for swimming for a few seconds. However, much longer time periods (over 45 sec) are required to generate ATP via glycolysis. Therefore, selection may have favored adaptation only at the arginine kinase locus.
Molecular techniques provide ancestral phylogenies of extant taxa with estimated branching times. Here we studied the pattern of ancestral phylogeny of extant taxa produced by branching (or cladogenesis) and extinction of taxa, assuming branching processes with time-dependent rates. (1) If the branching rate b and extinction rate c are constant, the semilog plot of the number of ancestral lineages over time is not a straight line but is curvilinear, with increasing slope toward the end, implying that ancestral phylogeny shows apparent increase in the branching rate near the present. The estimate of b and c based on nonlinear fitting is examined by computer simulation. The estimate of branching rate can be usable for a large phylogeny if b is greater than c, but the estimate of extinction rate c is unreliable because of large bias and variance. (2) Gradual decrease in the slope of the semilog plot of the number of ancestral lineages over time, as was observed in a phylogeny of bird families based on DNA hybridization data, can be explained equally well by either the decreasing branching rate or the increasing extinction rate. Infinitely many pairs of branching and extinction rates as functions of time can produce the same ancestral phylogeny. (3) An explosive branching event in the past would appear as a quick increase in the number of ancestral lineages. In contrast, mass extinction occurring in a brief period, if not accompanied by an increase in branching rate, does not produce any rapid change in the number of ancestral lineages at the time. (4) The condition in which the number of ancestral lineages of extant species changes in parallel with the actual number of species in the past is derived.
Expansions of population size leave characteristic signatures in mitochondrial "mismatch distributions." Consequently, these distributions can inform us about the history of changes in population size. Here, I study a simple model of population history that assumes that, t generations before the present, a population grows (or shrinks) suddenly from female size N0 to female size N1 . Although this model is simple, it often provides an accurate description of data generated by complex population histories. I develop statistical methods that estimate θ0 = 2uN0 , θ1 = 2uN1 , and τ = 2ut (where u is the mutation rate), and place a confidence region around these estimates. These estimators are well behaved, and insensitive to simplifying assumptions. Finally, I apply these methods to published mitochondrial data, and infer that a major expansion of the human population occurred during the late Pleistocene.
Phylogenies reconstructed from gene sequences can be used to investigate the tempo and mode of species diversification. Here we develop and use new statistical methods to infer past patterns of speciation and extinction from molecular phylogenies. Specifically, we test the null hypothesis that per-lineage speciation and extinction rates have remained constant through time. Rejection of this hypothesis may provide evidence for evolutionary events such as adaptive radiations or key adaptations. In contrast to previous approaches, our methods are robust to incomplete taxon sampling and are conservative with respect to extinction. Using simulation we investigate, first, the adverse effects of failing to take incomplete sampling into account and, second, the power and reliability of our tests. When applied to published phylogenies our tests suggest that, in some cases, speciation rates have decreased through time.
Reviews previous notions of what might cause speciation and extinction, and hypotheses that have predicted temporal patterns of evolutionary events. Discusses a new postulate relating to the 'turnover-pulse' (a concentration of turnover events against the time scale), arguing that global climatic forcing of speciation rhythms has been of major importance to the diversification of mammals on the huge continental landmass of Africa in the Neogene. The turnover-phase hypothesis uses concepts of evolutionary conservation, species' habitat-specificity and vicariance. -P.J.Jarvis
Community ecologists are increasingly aware that the regional history of taxon diversi- ecation can have an important ineuence on community structure. Likewise, systematists recognize that ecological context can have an important ineuence on the processes of speciation and extinction that create patterns of descent. We present a phylogenetic analysis of 33 species of a North American radiation of damseleies (Zygoptera: Coenagrionidae: Enallagma Selys), which have been well studied ecologically,toelucidatetheevolutionarymechanismsthathavecontributedtodifferencesindiversity between larvalhabitats(lakeswith and withouteshpredators).Analysis ofmolecular variation in 842 bp of the mitochondrial cytochrome oxidase I and II subunit and of the intervening Leu-tRNA and 37 morphological characters resulted in three well-deened clades that are only partially congruent with previous phylogenetic hypotheses. Molecular and morphological data partitions were signiecantly incongruent (p < .01). Lack of haplotype monophyly within species and small amounts of sequence divergence (<1%) between related species in three of the four clades suggest that recent, and parallel, speciation has been an importantsource of community diversity. Reconstruction of habitat preference over the phylogeny suggests that the greater species diversity in esh-containing lake habitats reeects the recency of shifts into the eshless lake habit, although a difference in speciation or extinction rates between the two habitats is difecult to exclude as an additional mechanism. (Coenagrionidae; habitat shifts; mitochondrial DNA; molecular systematics; Odonata; species diversity.)
We present evidence that in Enallagma damselflies there is a tactile recognition system whereby the female, once clasped in tandem, recognizes a conspecific male via the mechanical stimulation of his superior anal appendages on her mesostigmal plates, which are appropriately modified for this purpose. Similar systems, already suggested in Ischnura and Lestes, will probably be found in other odonates which have not secondarily developed female visual recognition systems. We suggest that the mechanical isolation sometimes observed in this and other genera may be an incidental result of changes in such a tactile recognition system during the formation of new species.
The concept of species flocks has been central to previous interpretations of patterns and processes of explosive species radiations within several groups of freshwater fishes. Here, molecular phylogenies of species-rich Sebastes rockfishes from the northeastern Pacific Ocean were used to test predictions of null theoretical models that assume random temporal placements of phylogenetic nodes. Similar appraisals were conducted using molecular data previously published for particular cichlid fishes in Africa that epitomize, by virtue of a rapid and recent radiation of species, the traditional concept of an intralacustrine 'species flock.' As gauged by the magnitudes of genetic divergence in cytochrome b sequences from mitochondrial DNA, as well as in allozymes, most speciation events in the Sebastes complex were far more ancient than those in the cichlids. However, statistical tests of the nodal placements in the Sebastes phylogeny suggest that speciation events in the rockfishes were temporally nonrandom, with significant clustering of cladogenetic events in time. Similar conclusions also apply to an ancient complex of icefishes (within the Notothenioidei) analyzed in the same fashion. Thus, the rockfishes (and icefishes) may be interpreted as ancient species flocks in the marine realm. The analyses exemplified in this report introduce a conceptual and operational approach for extending the concept of species flocks to additional environmental settings and evolutionary timescales.
Previous studies have shown that at least two lineages of Enallagma damselflies (Odonata: Coenagrionidae) shifted from inhabiting lakes with fish as top predators to inhabiting ponds and lakes with large dragonflies as the top predators. In adapting to living with the new predator type, these lineages evolved much greater swimming speeds to avoid attacking dragonflies. In this paper, I test whether biochemical adaptations to fuel swimming arose in concert with previously identified morphological changes that increase swimming speed. I assayed the mass-specific enzyme activities of three enzymes involved in fueling strenuous activity: pyruvate kinase and lactate dehydrogenase (enzymes involved in glycolysis) and arginine kinase (the enzyme that recharges the ATP pool). Enzyme activities were determined for 14 Enallagma species from across the genus. Species that coexist with dragonfly predators had significantly higher mass-specific arginine kinase activities than species that coexist with fish, and the results of evolutionary contrasts analyses indicate that this difference between the two groups is the result of evolutionary change associated with the habitat shifts of lineages from fish lakes to dragonfly lakes. Although significant evolution was documented for lactate dehydrogenase and pyruvate kinase across the genus, evolutionary change in the activities of these enzymes was not consistent with adaptation to coexisting with dragonfly predators. Swimming bouts to avoid dragonfly predators last for only a few seconds, and the action of arginine kinase to phosphorylate ADP to make ATP will extend the duration of maximal exertion for swimming for a few seconds. However, much longer time periods (over 45 sec) are required to generate ATP via glycolysis. Therefore, selection may have favored adaptation only at the arginine kinase locus.
— We studied sequence variation in 16S rDNA in 204 individuals from 37 populations of the land snail Candidula unifasciata (Poiret 1801) across the core species range in France, Switzerland, and Germany. Phylogeographic, nested clade, and coalescence analyses were used to elucidate the species evolutionary history. The study revealed the presence of two major evolutionary lineages that evolved in separate refuges in southeast France as result of previous fragmentation during the Pleistocene. Applying a recent extension of the nested clade analysis (Templeton 2001), we inferred that range expansions along river valleys in independent corridors to the north led eventually to a secondary contact zone of the major clades around the Geneva Basin. There is evidence supporting the idea that the formation of the secondary contact zone and the colonization of Germany might be postglacial events. The phylogeographic history inferred for C. unifasciata differs from general biogeographic patterns of postglacial colonization previously identified for other taxa, and it might represent a common model for species with restricted dispersal.
Behavior can play a mediating role in determining the selective pressures that influence the evolution of morphological structures. To examine this, I quantified patterns of morphological variation among larvae of Enallagma damselfly species (Odonata: Coenagrionidae) that use different behaviors to avoid the major predators found in each of two communities, lakes with and without fish. Specifically, I quantified the sizes and shapes of the abdomens and caudal lamellae (used for swimming) and legs for three species from fishless lakes and six species from lakes with fish. A preliminary cladistic analysis indicates that species within each lake type are not members of a single clade, which supports the conclusions of previous odonate taxonomists. Previous studies have shown that species in fishless lakes are very active, running and swimming frequently and at high rates of speed in the absence of predators, and they avoid their primary predators, large dragonflies, by swimming. These species have the widest abdomens, the largest caudal lamellae relative to overall body size, and the longest legs of the species studied, which should make them powerful swimmers and runners. Furthermore, species in fishless lakes are morphologically very similar to one another and differ greatly from fish-lake species, although each is more closely related to species in fish lakes. In contrast, species from lakes with fish move very slowly and infrequently in the absence of predators and do not attempt to evade attacking predators. However, despite their behavioral similarity, large interspecific variation in morphology exists among the fish-lake species, and the only morphological patterns were differences associated with membership in the two primary clades identified in the cladistic analysis. A modification of Felsenstein's (1985) method of evolutionary contrasts which allows character change to be isolated along single branches is introduced and is used to reconstruct the evolutionary histories of these characters. This analysis suggests that large increases in caudal lamella size, abdominal segment lengths and widths, and leg length accompany speciation events associated with habitat shifts from fish-lakes to fishless lakes. Following habitat shifts selection pressures exerted by dragonfly predation apparently favored swimming as an escape tactic, which mediated selection pressures onto morphologies used in swimming to increase swimming performance; morphological patterns in extant species reflect this adaptation to a new environment. Mechanisms by which behaviorally mediated selection could have accelerated evolutionary dynamics following founder events are discussed.
The rate of evolutionary morphological change in secondary sexual characters among species has traditionally been assumed to exceed that for non-sexual characters, giving rise to a larger degree of divergence. We used a large data set of independent evolutionary events of exaggerated secondary sexual feather characters across all birds to test whether that was the case. Comparative analyses revealed that secondary sexual tail feather characters diverged more than wing feathers in females, and we also found that secondary sexual head feather characters diverged more than tarsi in males, when only including intra-order comparisons in the analyses. These results are in the predicted direction, with secondary sexual characters diverging more than ordinary morphological traits, partially supporting the general impression that secondary sexual characters are more variable among species than ordinary morphological characters. However, the degree of divergence among secondary sexual characters was generally not much larger than that among ordinary characters. Some non-significant differences in divergence between secondary sexual characters and ordinary characters could be explained by the cost-reducing function of ordinary morphological traits. There was no evidence of significant differences in divergence between sexes for secondary sexual characters, maybe because of genetic correlations in morphology between the sexes. However, male tarsi diverged more than female tarsi, and sexual selection might play a role in this difference in divergence.
... There also appears to be a major phylogeographical break within E. whitii occurring in ... Akaike Information Criterion (AIC) to select the most appropriate model of molecular evolution for ... We tested a range of hypotheses regarding the systematics and biogeographical patterns of ...
The vagaries of history lead to the prediction that repeated instances of evolutionary diversification will lead to disparate outcomes even if starting conditions are similar. We tested this proposition by examining the evolutionary radiation of Anolis lizards on the four islands of the Greater Antilles. Morphometric analyses indicate that the same set of habitat specialists, termed ecomorphs, occurs on all four islands. Although these similar assemblages could result from a single evolutionary origin of each ecomorph, followed by dispersal or vicariance, phylogenetic analysis indicates that the ecomorphs originated independently on each island. Thus, adaptive radiation in similar environments can overcome historical contingencies to produce strikingly similar evolutionary outcomes.
The 27 species of Dendroica wood-warblers represent North America's most spectacular avian adaptive radiation. Dendroica species exhibit high levels of local sympatry and differ in plumage and song, but the group contrasts with other well–know avian adaptive radiations such as the Hawaiian honeycreepers and Galapagos finches in that Dendroica species have differentiated modestly in morphometric traits related to foraging. Instead, sympatric Dendroica tend to partition resources behaviourally and they have become a widely cited example of competitive exclusion. We explore the temporal structure of Dendroica diversification via a phylogeny based on 3639 nucleotides of protein–coding mitochondrial DNA (mtDNA). The taxa sampled include 60 individuals representing 24 Dendroica species and a variety of other paruline warbler and outgroup species. Mitochondrial divergences among Dendroica species were generally large (mean pairwise interspecific distances, 10.0%) and many species were rooted in a basal polytomy.
The prevalence of long terminal branches indicates that these species have evolved efficient isolating mechanisms that hav prevented mtDNA introgression despite the many opportunities for hybridization resulting from local sympatry. Comparison with a null model of random bifurcation–extinction demonstrate that cladogenesis in Dendroica has been clustered non–randomly with respect to time, with a significant burst of speciation occurring early in the histor of the genus, possibly as long ago as the Late Miocene or Early Pliocene periods. Although this non–random clustering of speciatio is consistent with the pattern expected of an adaptive radiation, the age of the Dendroica radiation suggests it is an ‘ancient species flock’ in which most extant species represent lineages that have long been evolutionaril independent.
The ecology of the component species of an adaptive radiation is likely to be influenced by the form of the founding ancestor to the radiation, its timing, and rates of speciation and extinction. These historical features complement environmental se- lection pressures. They imply that, if the history of the species' ra- diations are very different, ecological communities are unlikely to be completely convergent even when placed in identical environments. We compare the adaptive radiation of the Dendroica warblers of North America with that of the Phylloscopus warblers of Asia. We consider the ecology of the species in two localities where species' diversity is very high (New Hampshire, U.S.A., and Kashmir, India, respectively) and contrast the history of the two radiations on the basis of a molecular (mitochondrial cytochrome b) phylogeny. By comparison with the Phylloscopus, the Dendroica are on average larger and morphologically more similar to one another. Although there is some similarity between the Dendroica and Phylloscopus communi- ties, they differ in foraging behavior and in associations of mor- phology with ecological variables. The Dendroica likely reflect an early Pliocene radiation and are two to four times younger than the Phyl- loscopus. They probably had a colorful sexually dichromatic ancestor, implicating sexual selection in the production of the many ecolog- ically similar species. The Phylloscopus are much older and probably had a drab, monomorphic ancestor. Given the difference in ages of the two radiations, it is plausible that the close species' packing of the Dendroica warblers is a transient phenomenon. If this is the case, community structure evolves on the timescales of millions of years. Differences in ancestry and timing of the species' radiations can be related to the different biogeography of the two regions. This implies that the historical imprint on adaptive radiations could be predicted on the basis of the attributes of ancestors and biogeographical context.
In previous research I have shown,that fish predation contributes to the exclusion of a group of Enallagma,species (Odonata: Zygoptera) from lakes containing fish, whereas dragonfly predation contributes to the exclusion of another group of Enal- lagrna species from fishless lakes. In the study reported in this paper I performed a series of laboratory experiments to identify behavioral differences between the two groups that could contribute to their differential vulnerabilities to the two predators. In one experiment I observed the behaviors of four Enallagma species. two from fishless lakes and two from
Many authors have suggested that sexual selection by female choice may increase the speciation rate and hence generate taxonomic diversity. Using sister taxa comparisons, we find a significant positive correlation between the proportion of sexually dichromatic species within taxa of passerine birds, and the number of species in those taxa. Theory predicts this result if sexual dichromatism in passerines has evolved through the action of female choice.
Direct comparison of ancient extinctions to the present-day situation is difficult, because quantitative palaeontological data come primarily from marine invertebrates, fossilized species are usually drawn from the more abundant and widespread taxa, and time resolution is rarely better than 10(3)-10(4) years. A growing array of techniques permits quantitative error estimates on some of these potential biases, and allows calculation of species extinction intensities from genus-level data, which are more robust. Extensive as today's species losses probably are, they have yet to equal any of the Big Five mass extinctions. Background extinction patterns are potential sources of insight regarding present-day biotic losses; over 90% of past species extinction has occurred at times other than the Big Five mass extinctions. Mean durations of fossil species vary by more than an order of magnitude even within clades, rendering uninformative any global average for background extinction. Taxon-specific variation is evidently related to intrinsic biotic factors such as geographic range and population size. Approaches to extinction analysis and prediction based on morphological variety or biodisparity should be explored as an adjunct or alternative to taxon inventories or phylogenetic metrics. Rebounds from mass extinctions are geologically rapid but ecologically slow; biodiversity recovery and the re-establishment of some communities typically requires 5-10 million years.
Molecular techniques provide ancestral phylogenies of extant taxa with estimated branching times. Here we studied the pattern of ancestral phylogeny of extant taxa produced by branching (or cladogenesis) and extinction of taxa, assuming branching processes with time-dependent rates. (1) If the branching rate b and extinction rate c are constant, the semilog plot of the number of ancestral lineages over time is not a straight line but is curvilinear, with increasing slope toward the end, implying that ancestral phylogeny shows apparent increase in the branching rate near the present. The estimate of b and c based on nonlinear fitting is examined by computer simulation. The estimate of branching rate can be usable for a large phylogeny if b is greater than c, but the estimate of extinction rate c is unreliable because of large bias and variance. (2) Gradual decrease in the slope of the semilog plot of the number of ancestral lineages over time, as was observed in a phylogeny of bird families based on DNA hybridization data, can be explained equally well by either the decreasing branching rate or the increasing extinction rate. Infinitely many pairs of branching and extinction rates as functions of time can produce the same ancestral phylogeny. (3) An explosive branching event in the past would appear as a quick increase in the number of ancestral lineages. In contrast, mass extinction occurring in a brief period, if not accompanied by an increase in branching rate, does not produce any rapid change in the number of ancestral lineages at the time. (4) The condition in which the number of ancestral lineages of extant species changes in parallel with the actual number of species in the past is derived.
Two species, found as larvae in fishless lakes, and 2 species, found as larvae in lakes supporting well-developed fish faunas, dispersed very few adults to adjacent lakes (≤ 1 km apart). Another species, found in winterkill lakes that periodically cycle between the fish-containing and fishless condition, dispersed large numbers of adults to adjacent lakes. The species inhabiting fishless lakes cannot discriminate between fishless and fish-containing lakes. Species differences in the propensity to disperse are attributed to the constancy of the fishless and fish-containing condition of the lakes inhabited by species. The mechanisms causing species differences in movement between lakes appear to be differences in their propensity to leave natal lakes, not active selection of different lake types. -from Author
One group of Enallagma (Odonata: Coenagrionidae) is found as larvae only in Michigan lakes containing fish, while the remaining species are found as larvae only in fishless lakes. Dragonfly larvae were the most abundant invertebrate predator group in both lake types, with each lake type supporting a characteristic set of dragonfly species, as in the damselflies. Fish were also potentially major predators in lakes containing fish. Also, Enallagma densities in both lake types were among the highest reported in the literature, suggesting that density-dependent competitive interactions may potentially contribute to maintaining the Enallagma species distributions. Experiments demonstrated that predation by large dragonflies in fishless lakes and predation by fish in fish-containing lakes are 2 major environmental factors maintaining the Enallagma species distributions. Density-dependent competitive interactions among the Enallagma species were only apparent in the fishless lakes, affected species from both groups similarly, and altered their growth but not their survival. -from Author
Combining phylogeographic data from mitochondrial DNA (mtDNA) of Nearctic and Palearctic freshwater and anadromous fishes, we used a comparative approach to assess the influence of historical events on evolutionary patterns and processes in regional fish faunas. Specifically, we (i) determined whether regional faunas differentially affected by Pleistocene glaciations show predictable differences in phylogeographic patterns; (ii) evaluated how processes of divergence and speciation have been influenced by such differential responses; and (iii) assessed the general contribution of phylogeographic studies to conservation issues. Comparisons among case studies revealed fundamental differences in phylogeographic patterns among regional faunas. Tree topologies were typically deeper for species from nonglaciated regions compared to northern species, whereas species with partially glaciated ranges were intermediate in their characteristics. Phylogeographic patterns were strikingly similar among southern species, whereas species in glaciated areas showed reduced concordance. The extent and locations of secondary contact among mtDNA lineages varied greatly among northern species, resulting in reduced intraspecific concordance of genetic markers for some northern species. Regression analysis of phylogeographic data for 42 species revealed significant latitudinal shifts in intraspecific genetic diversity. Both relative nucleotide diversity and estimates of evolutionary effective population size showed significant breakpoints matching the median latitude for the southern limit of the Pleistocene glaciations. Similarly, analysis of clade depth of phylogenetically distinct lineages vs. area occupied showed that evolutionary dispersal rates of species from glaciated and nonglaciated regions differed by two orders of magnitude. A negative relationship was also found between sequence divergence among sister species as a function of their median distributional latitude, indicating that recent bursts of speciation events have occurred in deglaciated habitats. Phylogeographic evidence for parallel evolution of sympatric northern species pairs in postglacial times suggested that differentiation of cospecific morphotypes may be driven by ecological release. Altogether, these results demonstrate that comparative phylogeography can be used to evaluate not only phylogeographic patterns but also evolutionary processes. As well as having significant implications for conservation programs, this approach enables new avenues of research for examining the regional, historical, and ecological factors involved in shaping intraspecific genetic diversity.
Variations in Earth's orbit with periods of 10–100 thousand years (kyr) (Milankovitch oscillations) have led to recurrent and rapid climatic shifts throughout Earth's history. These cause changes in the geographical distributions of clades, which we term orbitally forced range dynamics (ORD). The magnitude of ORD varies geographically, e.g., with latitude. Climatic shifts cause extinction, splitting, and merging of gene pools and clades. They select among individuals and clades for traits enhancing the ability to survive in situ and to establish new populations. There is also nonadaptive sorting caused by the large geographical variation in ORD, as only gene pools that are in the right place when climate shifts survive. ORD lead to sorting at many levels of genealogic inclusiveness. Clades that have survived climatic shifts during at least one entire period of the longest significant Milankovitch oscillations (100 kyr), we name β-clades. The products of more recent cladogenesis are α-clades, which are always nested within a β-clade. We conclude that ORD may promote α-clade formation but curb rates of β-clade formation. In areas with little ORD, where gene pools persist without going extinct or merging, clade splits and divergence may accumulate leading to high rates of β-clade formation and β-anagenesis (evolutionary change persisting >100 kyr). High ORD should lead to low numbers of β-clades, β-clades with low levels of spatial genetic divergence, little geographical subdivision and large ranges, organisms with high vagility and low specialization, high proportions of β-clades formed by polyploidization, and little β-anagenesis. We predict global and interregional geographic patterns in these variables caused by differential ORD. Thus, ORD potentially explains a wide array of patterns, suggesting ORD as a fundamental factor in evolution. The vulnerability of biotas to many human activities should vary with the magnitude of ORD.