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Frequency of flower visits per hour per flower to Ipomoea bahiensis, I. nil, and Merremia aegyptia at Estação Ecológica do Seridó, Brazil (n = 40 flowers per species, 4 days of observation)
Source publication
During the rainy season many species of Convolvulaceae bloom simultaneously in the Caatinga of northeast Brazil. In a Caatinga
nature reserve we studied pollination and breeding systems of three sympatric species of Convolvulaceae, Ipomoea bahiensis, I. nil, and Merremia aegyptia, focusing on pollen partitioning among flower visitors and pollen flo...
Contexts in source publication
Context 1
... flower visitation rate was much higher to M. aegyptia (73.5 visits per flower per day) than to I. bahiensis (7.4 visits per flower per day) and I. nil (3.5 visits per flower per day) (Fig. 3) due to the high abundance of honey bee workers (Fig. 4c). The main period of flower visits, 8:00-11:00 h, was similar in the three species. In this time we recorded 73% of the flower visits in I. bahiensis, 95% in I. nil, and 73% in M. aegyptia (Fig. 3). The different bee species, however, showed slightly different peaks in visitation ...
Context 2
... to I. bahiensis (7.4 visits per flower per day) and I. nil (3.5 visits per flower per day) (Fig. 3) due to the high abundance of honey bee workers (Fig. 4c). The main period of flower visits, 8:00-11:00 h, was similar in the three species. In this time we recorded 73% of the flower visits in I. bahiensis, 95% in I. nil, and 73% in M. aegyptia (Fig. 3). The different bee species, however, showed slightly different peaks in visitation frequency: bees of Melitoma segmentaria and Melitomella murihirta visited flowers of I. bahiensis more frequently between 8:00 and 10:00 h, and bees of Lithurgus huberi between 11:00 and 12:00 h (Fig. 4a). In I. nil, flower visits of L. huberi were most ...
Similar publications
Ipomoea pes-caprae (Convolvulaceae), a pantropical plant with sea-drifted seeds, is found globally in the littoral areas of tropical and subtropical regions. Unusual long-distance seed dispersal has been believed to be responsible for its extraordinarily wide distribution; however, the actual level of inter-population migration has never been studi...
Citations
... flowers is a more intricate relationship than currently reported. This makes sense, since Melitomella grisescens and Melitoma segmentaria (and probably also M. osmiodes) are oligolectic bees specialized on Convolvulaceae (Pick and Schlindwein 2011). The female bees of these species consistently use a small set of Convolvulaceae species as pollen source, suggesting that males might similarly choose the same species for overnight stays and find females in next day. ...
... Another interesting aspect that makes this interaction possible is the timing of anthesis of I. carnea. For some of the most abundant Convolvulaceae species visited by Emphorini bees in the Caatinga, such as Ipomoea bahiensis, I. nil, and Merremia aegyptia (Pick and Schlindwein 2011), flower anthesis occurs synchronously in the early morning and close around noon or in the mid-afternoon, when male bees are often still active (Kill & Ranga 2000, Maimoni-Rodella 2007, Gimenes et al. 2021. As a result, the access of male bees to the flowers is no longer possible in the late afternoon. ...
The present study describes the behavior of male Emphorini bees in exploiting Convolvulaceae flowers as sleeping-sheltering place. The observations occurred inadvertently during a field study in an Agroforestry System in the Caatinga region, near the banks of the São Francisco River in Petrolina, Pernambuco – NE-Brazil. Males were observed and collected in wilted flowers of Ipomoea carnea (Convolvulaceae) during the evening. The sampling revealed nine Emphorini bees, belonging to three oligolectic species specialized on Convolvulaceae. We propose that the infundibuliform morphology of Ipomoea carnea flowers and the varied timing of anthesis could influence the choice of these flowers as overnight resting places. Furthermore, we endorse the idea present in the literature that males of oligolectic bees generally engage in patrolling flowers utilized by females, thereby enhancing the chances of encountering potential mates, making these flowers rendezvous places. The observation of this behavior highlights the interdependence between bees and plants and raises the possibility that the loss of these flowers could negatively impact bees not only in a nutrition aspect but also regarding shelter and reproduction.
... Self-incompatibility has also been reported in other species in the Convolvulaceae, such as Ipomoea pandurata (Stucky and Beckmann 1982), I. pescaprae (Devall and Thein 1992), I. cairica (Jia et al. 2007) and I. bahiensis (Pick and Schlindwein 2011). However, the Convolvulaceae family is highly diverse, and other mating systems are common, including self-compatible (Pick and Schlindwein 2011;Delgado-Dávila et al. 2016) and mixed mating systems (Chang and Rausher 1999;McMullen 2009;Wright et al. 2012). Self-incompatibility is well-known as an important and prevalent mechanism that promotes outcrossing in angiosperms (Whitehouse 1950;Richards 1997;Allen and Hiscock 2008;Narayanapur et al. 2018) and the results of our controlled pollination experiments, coupled with the findings from our pollinator observations, indicate that both A. versicolor and A. mekongensis are reliant on pollinators to promote outcrossing. ...
... Our pollinator observations indicate that both A. versicolor and A. mekongensis are pollinated by carpenter bees. Previous studies have generally reported that Convolvulaceae species are mainly pollinated by bees (Galetto and Bernadello 2004;Maimoni-Rodella and Yanagizawa 2007;Pick and Schlindwein 2011;Hassa et al. 2023) or by bees and butterflies (Hassa et al. 2020;Jirabanjongjit et al. 2021) or by hawkmoths (Willmott and Burquez 1996;McMullen 2009;Chitchak et al. 2022). Pollination studies of Argyreia are scarce compared to sister genera such Ipomoea, but Chitchak et al. (2018) did report that Xylocopa nasalis visits Argyreia gyrobracteata and receives pollen on its head. ...
Argyreia versicolor (Kerr) Staples & Traiperm and A. mekongensis Gagnep. & Courchet are extremely rare plant species. The former had not been seen for nearly 100 years, until two individuals were found in Thailand in 2018, and only a handful of populations are known for the latter. The aims of this study were to examine the breeding systems of A. versicolor and A. mekongensis using pollination experiments and to determine their potential pollinators via floral observations. Our controlled pollination experiments uncovered the self-incompatibility of both species. Pollinator censuses indicated that females of two carpenter bee species, Xylocopa aestuans and X. latipes, were the predominant floral visitors for both Argyreia species. Our observations confirmed a harmonious match between the floral shape of both Argyreia species and the body sizes of these pollinators, ensuring effective pollen transfer and validating their role as putative pollinators. In line with the high frequency of pollinator visits observed, our controlled pollination experiments found no evidence of pollen limitation under field conditions. The findings of this study hold significance for the conservation of these endangered species, yet the situation is dire for A. versicolor, with one of the two individuals under study recently lost. Hence, it is crucial to intensify monitoring efforts for the species, aiming to identify additional individuals for potential inclusion in an ex-situ conservation program. Simultaneously, safeguarding the habitat of these plant species and their pollinators will be critical.
... Note: Significant differences at p < 0.05 in bold. (Bullock et al., 1987;Pacheco-Filho et al., 2011;Paz et al., 2013;Pick & Schlindwein, 2011;Wolfe & Sowell, 2006). We think that I. triloba may be established as an invasive alien plant with a wide range because it is a generalist that can accommodate various pollinators between regions. ...
... Our finding was consistent with previous studies that reported self-compatible breeding systems in several species of Ipomoea, including I. hederacea var. integriuscula (Hull-Sanders et al., 2005), I. nil (Pick & Schlindwein, 2011), I. carnea subsp. fistulosa (Paz et al., 2013), and I. aquatica (Hassa et al., 2020). ...
Ipomoea triloba L., an annual twining herb, is considered an alien invasive species and is distributed all around the globe including tropical Asia. It affects the yield of various economically important crops. Studies on floral phenology and reproductive biology are fundamental for the development of management strategies and the conservation of plants. Hence, we investigated the phenology, floral biology, pollen viability, stigma receptivity, pollination mechanism, and reproductive success of I. triloba at two different locations in one of the global biodiversity hotspots. Floral anthesis was diurnal, starting at 6:30 a.m. and lasting until 7:00 a.m. Pollen viability and stigma receptivity were found to coincide, thus suggesting the species was homogamous. The flowers were mostly visited and pollinated by sweat bees (Halictidae), blue‐banded bees ( Amegilla sp.), flies ( Mesembrius sp.), and butterflies ( Appias olferna , Pelopidas agna , and Zizina otis ). Further, the pollinator visitation frequency showed a moderately positive correlation with the number of open flowers in both study populations. The plant produced fruits in the absence of pollinators in self‐pollination treatments, indicating a self‐compatible breeding system and dependency on insect pollination for reproductive success. Further, pollen supplementation significantly enhanced the fruit setting and mean seed per fruit at both study sites, suggesting pollen limitation. Additionally, pollen production and pollen/ovule ratio also indicated the facultative autogamous breeding system in I. triloba . Overall, these reproductive characteristics such as mixed mating systems and generalist insect visitation may allow the invasive I. triloba to establish new populations from low numbers of propagules.
... Analysis of nest provisions (e.g. [84]) was considered to be the equivalent of 10 analyzed pollen loads for species demonstrated to be specialized, but was not used for species found to be generalized due to the impossibility of relating nest contents to a specific number of pollen loads. A total of 13 specialized bee species in our dataset were classified based solely on nest content analysis. ...
Background
Within the Hymenoptera, bees are notable for their relationship with flowering plants, being almost entirely dependent on plant pollen and nectar. Though functionally herbivorous, as a result of their role as pollinators, bees have received comparatively little attention as models for insect herbivory. Bees often display dietary specialization, but quantitative comparison against other herbivorous insects has not previously been conducted.
Results
In the most comprehensive analysis to date for 860 bee species, dietary specialization amounted to 50.1% of studied species collecting pollen from between 1 and 2 botanical families with a relatively long tail of dietary generalists, with 11.1% of species collecting from more than 10 botanical families. This distribution deviated from the truncated Pareto distribution of dietary breadth seen in other herbivorous insect lineages. However, this deviation was predominantly due to eusocial bee lineages, which show a range of dietary breadths that conformed to a normal distribution, while solitary bees show a typical truncated distribution not strongly different from other herbivorous insects. We hypothesize that the relatively low level of dietary specialization in bees as a whole reflects the relaxation of the constraints typically observed in herbivorous insects with a comparatively reduced importance of plant chemistry and comparatively increased importance of phenology and foraging efficiency. The long flight periods of eusocial bees that are necessary to allow overlapping generations both allows and necessitates the use of multiple flowering resources, whereas solitary bees with short flight periods have more limited access to varied resources within a constrained activity period.
Conclusions
Collectively, solitary bees show slightly lower specialization compared to other herbivorous insects, possibly due to their balanced relationship with plants, rather than direct antagonism such as seen in the direct consumption of plant tissues. An additional factor may be the mediocre diversity of bees at low latitudes combined with low levels of dietary specialization, whereas these areas typically display a high rate of specialization by herbivorous insects in general. Though the most important factors structuring dietary specialization in bees appear to differ from many other herbivorous insects, solitary bees show a surprisingly similar overall pattern of dietary specialization.
... Observational studies measure encounters within or between species using ethograms or annotations specifying the types of interactions that occur and can include competition (Wallace and Temple, 1987), mutualism (Pick and Schlindwein, 2011) or predation (Simon, 1975). These interactions can then be grouped into intraspecific and interspecific competition and used to calculate a competition coefficient (Cunningham et al., 2009). ...
Mechanistic niche models are computational tools developed using biophysical principles to address grand challenges in ecology and evolution, such as the mechanisms that shape the fundamental niche and the adaptive significance of traits. Here, we review the empirical basis of mechanistic niche models in biophysical ecology, which are used to answer a broad array of questions in ecology, evolution and global change biology. We describe the experiments and observations that are frequently used to parameterize these models and how these empirical data are then incorporated into mechanistic niche models to predict performance, growth, survival and reproduction. We focus on the physiological, behavioral and morphological traits that are frequently measured and then integrated into these models. We also review the empirical approaches used to incorporate evolutionary processes, phenotypic plasticity and biotic interactions. We discuss the importance of validation experiments and observations in verifying underlying assumptions and complex processes. Despite the reliance of mechanistic niche models on biophysical theory, empirical data have and will continue to play an essential role in their development and implementation.
... The Convolvulaceae is a large family with over 1,840 known species (sensu [23]) and exhibiting diverse floral morphologies [23][24][25], breeding systems [26][27][28], and pollinators [29][30][31]. However, most research on the breeding systems and pollinators of the Convolvulaceae has been conducted in the Neotropics [18,28,[32][33][34] and temperate zones [35][36][37][38], and we still lack information from paleotropical areas (but see [39][40][41]. Such underrepresentation needs to be remedied, especially given that the center of diversity for many Convolvulaceae genera is located in the Paleotropics (e.g., Argyreia Lour., Erycibe Roxb., Stictocardia Hallier f.) [23]. ...
... Ipomoea nil was visited by 11 bee taxa in southeastern Brazil, and six were classified as efficient pollinators [35]. In northeastern Brazil, flowers of I. nil were visited by 10 bee taxa and one butterfly species, but 80% of visits were by Lithurgus huberi in the family Megachilidae [33]. Our study found that while the potential pollinators of I. nil are diverse, Amegilla bees were by far the most frequent visitors. ...
Background
The Convolvulaceae is a large family containing species exhibiting a range of breeding systems and pollinated by diverse animal taxa. We studied the pollination ecology of 15 Convolvulaceae species, representing seven genera (Argyreia Lour., Camonea Raf., Evolvulus L., Hewittia Wight & Arn., Ipomoea L., Merremia Dennst. ex Endl., and Operculina Silva Manso), in northeastern Thailand, a family that is highly diverse yet understudied in the paleotropics. Specifically, we studied their compatibility systems and degrees of pollinator dependency using pollination experiments, examined pollinator composition and visitation rates using video observation, and determined if there is an association between pollinator visitation rates and degree of pollinator dependence.
Results
Our results showed that most species are self-compatible, but the degree of pollinator dependence varies. Six species were found to be highly dependent on pollinators, as two are self-incompatible and four are self-compatible but had reduced seed set when pollinators were excluded, possibly due to herkogamy. Seven species showed low dependence on pollinators and seed set remained high when pollinators were excluded. Pollinator dependence was inconclusive for two species as seed set was low in all pollination treatments. We also found an association between pollinator visitation rates and degree of pollinator dependence. Specifically, species exhibiting high pollinator dependence received frequent visits from pollinators, while species exhibiting low pollinator dependence either received frequent visits from pollinators (and received high amounts of xenogamous pollen) or infrequent visits from pollinators (and received significantly lower amounts of xenogamous pollen). Most of our study species were primarily visited by bees (e.g., Lasioglossum, Amegilla, Apis, and meliponines), with the exception of one night-blooming species that was visited primarily by crepuscular butterflies and hawkmoths.
Conclusions
The cumulative findings of this study demonstrate how pollinator dependence is influenced by breeding system, and suggest that pollinator visitation is consistently high for species exhibiting high pollinator dependence but varies across species exhibiting low pollinator dependence. Our findings are also important for assessing the conservation risks of paleotropical Convolvulaceae.
... The pervasive nature of interspecific pollination in plant populations sets the ecological context for the evolution of strategies to avoid or ameliorate the costs of pollinator sharing with neighbors (Arceo- Gómez and Ashman, 2011;Ashman and Arceo-Gómez, 2013;Arceo-Gómez et al., 2016;Fang et al., 2019;Arceo-Gómez, 2021). Plants may reduce the number of shared pollinators, fully partition the pollinator community (Armbruster and Herzig, 1984;Wolfe and Sowell, 2006;Pick and Schlindwein, 2011), or use the same pollinator in different ways. The negative effects of using the same pollinator species can be reduced or eliminated by plants reducing phenological overlap during the flowering season or having flowers open at different times of the day (Armbruster, 1985;Stone et al., 1998;Raine et al., 2007;Botes et al., 2008). ...
Premise
Linum suffruticosum shows variations in pollinator fit, pollen pickup, and local pollinators that predict pollen deposition rates. The species often coflowers with other Linum species using the same pollinators. We investigated whether L. suffruticosum trait variation could be explained by local patterns of pollinator sharing and associated evolution to reduce interspecific pollen transfer.
Methods
Pollinator observations were made in different localities (single species, coflowering with other congeners). Floral traits were measured to detect differences across populations and from coflowering species. Reproductive costs were quantified using interspecific hand pollinations and measures of pollen‐tube formation, combined with observations of pollen arrival on stigmas and pollen‐tube formation after natural pollination in allopatric and sympatric localities.
Results
The size and identity of the most important pollinator of L. suffruticosum and whether there was pollinator sharing with coflowering species appeared to explain floral trait variation related to pollinator fit. The morphological overlap of the flowers of L. suffruticosum with those of coflowering species varied, depending on coflowering species identity. A post‐pollination incompatibility system maintains reproductive isolation, but conspecific pollen‐tube formation was lower after heterospecific pollination. Under natural pollination at sites of coflowering with congeners, conspecific pollen‐tube formation was lower than at single‐species localities.
Conclusions
Trait variation in L. suffruticosum appears to respond to the most important local pollinator. Locally, incomplete pollinator partitioning might cause interspecific pollination, imposing reproductive costs. These reproductive costs may generate selection on floral traits for reduced morphological overlap with coflowering congeners, leading to the evolution of pollination ecotypes.
... BB) are the main pollinators of Convolvulaceae in the Caatinga andMelitoma shows a narrow relationship with this plant family(Pick & Schlindwein, 2011). Finally, small and social bees, like Meliponini and Halictidae, were mainly captured with pan traps and at lower heights.The association between Halictidae and pan traps in general has beenshown by other studies(Gonçalves & Oliveira, 2013; Krug & Alvesdos-Santos, 2008), but not for Meliponini. ...
1. To sample bee communities, a combination of methods is necessary, the most common being hand netting (HN) and pan traps (PT). However, there has been little exploration into how vertical distribution of PT can improve their sampling efficiency, also taking the temporal variation of floral resources into account.
2. Here, we analysed the properties of bee communities sampled with PT at different heights (1.6 and 4.0 m) compared with PTs close to the ground, HN and large blue bucket trap (BB). In addition, we tested the effect of variation in the availability of floral resources on the performance of each method. Bees were collected in fragments of the Brazilian Caatinga.
3. We captured 60 bee species with PTs, HN and BB, with significant increases in the sample coverage with elevated bowls (BB = 56.7%, HN = 60.0%, PT0.3 m = 23.3%, PT1.6 m = 36.7%, PT4.0 m = 50.0%). Elevating the bowls increased the sampling of bees with larger body size. Considering the three heights, PTs registered similar richness compared to HN and BB, but differed in the composition of species and ecological traits.
4. When floral resource availability was greater, the abundance and richness of bees caught in PTs decreased, however, the elevated PT increased their ecological uniqueness (degree of uniqueness of the samples in terms of community composition). Thus, elevating PTs enables the capture of bees that forage at a specific height when floral resources increase.
5. Our results highlight the importance of the vertical distribution of PT for sampling bees, since it improves their performance and its complementarity with other methods.
... The measured overall high pollen gain (> 50%) of crepuscular Ptiloglossa from bat-pollinated Pseudobombax longiflorum approximates that of narrow bee-plant relationships, such as those of oligolectic bee species and their specific host plants (Schlindwein et al., 2005;Pick et al., 2011;Carvalho & Schlindwein, 2011;Siriani-Oliveira et al., 2018;Cerceau et al., 2019), albeit with the difference that bees in the studied bat-pollinated species do not contribute to the pollination of their hosts. ...
The shift in flight activity from daylight to twilight in crepuscular bees is assumed to have evolved to escape competitors, but quantitative confirmation of this hypothesis has never been demonstrated clearly. Pseudobombax longiflorum is a chiropterophilous plant, with flowers presenting large amounts of pollen throughout anthesis, thus attracting not only nocturnal visitors, but also crepuscular and diurnal bees. In this dynamic system, the fraction of pollen that flows to different visitors and the putative role of bees in pollination remain unknown. We analysed floral biology, the frequency of visitors in periods with different light intensities and the rate of pollen removal by each visitor group. A pollinator-exclusion experiment showed that bees were not pollinators of Pseudobombax longiflorum, although they collected > 60% of the pollen from their flowers. Crepuscular bees gained the greatest amount of pollen in the few minutes when they foraged without either nocturnal or diurnal competitors, confirming the advantage of foraging under low light. During the short twilight period, these bees foraged alone and removed 26.5 and 15 times more pollen per minute than nocturnal and diurnal visitors, respectively. Therefore, pollen removal by crepuscular bees is particularly efficient when they forage in the brief period while competitors are absent.
... The measured overall high pollen gain (> 50%) of crepuscular Ptiloglossa from bat-pollinated Pseudobombax longiflorum approximates that of narrow bee-plant relationships, such as those of oligolectic bee species and their specific host plants (Schlindwein et al., 2005;Pick et al., 2011;Carvalho & Schlindwein, 2011;Siriani-Oliveira et al., 2018;Cerceau et al., 2019), albeit with the difference that bees in the studied bat-pollinated species do not contribute to the pollination of their hosts. ...
The shift in flight activity from daylight to twilight in crepuscular bees is assumed to have evolved to escape competitors, but quantitative confirmation of this hypothesis has never been demonstrated clearly. Pseudobombax longiflorum is a chiropterophilous plant, with flowers presenting large amounts of pollen throughout anthesis, thus attracting not only nocturnal visitors, but also crepuscular and diurnal bees. In this dynamic system, the fraction of pollen that flows to different visitors and the putative role of bees in pollination remain unknown. We analysed floral biology, the frequency of visitors in periods with different light intensities and the rate of pollen removal by each visitor group. A pollinator-exclusion experiment showed that bees were not pollinators of Pseudobombax longiflorum, although they collected > 60% of the pollen from their flowers. Crepuscular bees gained the greatest amount of pollen in the few minutes when they foraged without either nocturnal or diurnal competitors, confirming the advantage of foraging under low light. During the short twilight period, these bees foraged alone and removed 26.5 and 15 times more pollen per minute than nocturnal and diurnal visitors, respectively. Therefore, pollen removal by crepuscular bees is particularly efficient when they forage in the brief period while competitors are absent. ADDITIONAL KEYWORDS: floral resource collection-nocturnal bees-pollen competition-pollen fate-pollination-Pseudobombax-Ptiloglossa.
