Figure - available from: Zoomorphology
This content is subject to copyright. Terms and conditions apply.
Linear measurements of orthopterans considered in this paper. The specimen corresponds to a male of Dichroplus pratensis Bruner (Caelifera: Acrididae: Melanoplinae), a Neotropical grasshopper. Drawing by Talita Ferreira Amado
Source publication
1. Body size influences the way that organisms both perform their locomotor activities and perceive their environment. Allometry of insect legs with respect to body size is affected by many factors such as ontogenetic constraints and natural selection. Negative allometry, positive allometry, or isometry could result from different mechanisms influe...
Citations
... ; https://doi.org/10.1101/2024.04.15.589523 doi: bioRxiv preprint a U-shaped body posture after jumping to stabilize mid-air and land ventrally on water surfaces [51]. While planthopper nymphs and immature stages of other jumping insects, such as leafhoppers and Orthoptera (grasshoppers, crickets, and katydids), are also capable of jumping, research into their midair body control is lacking [52,53]. To date, only two related studies have investigated the mid-air behavior of spotted lanternfly nymphs, uncovering and modelling their use of legs to slow rotations mid-air, which was shown to assist in landing success [54,55]. ...
The striking appearance of wax ‘tails’ — posterior wax projections on planthopper nymphs — has captivated entomologists and naturalists alike. Despite their intriguing presence, the functional roles of these structures remain largely unexplored. This study leverages high-speed imaging to uncover the biomechanical implications of these wax formations in the aerial dynamics of planthopper nymphs ( Ricania sp .). We quantitatively demonstrate that removing wax tails significantly increases body rotations during jumps. Specifically, nymphs without wax projections undergo continuous rotations, averaging 4.3 ± 1.9 per jump, in contrast to wax-intact nymphs, who narrowly complete a full rotation, averaging only 0.7 ± 0.2 per jump. This suggests that wax structures effectively counteract rotation through aerodynamic drag forces. These stark differences in body rotation correlate with landing success: nymphs with wax intact achieve a near perfect landing rate of 98.5%, while those without wax manage only a 35.5% success rate. Jump trajectory analysis reveals transitions from parabolic to Tartaglia shapes at higher take-off velocities for wax-intact nymphs, illustrating how wax structures assist nymphs in achieving stable, controlled descents. Our findings confirm the aerodynamic self-righting functionality of wax tails in stabilizing planthopper landings, advancing our understanding of the complex interplay between wax morphology and aerial maneuverability, with broader implications for the evolution of flight in wingless insects and bioinspired robotics.
... In wild-caught bush-crickets, we observed a weak negative association between elevation and traits only for pronotum width and length of femur, tibia and ovipositor. As this pattern was not confirmed in the lab, it indicates that morphological variation in the field is likely the result of environmentally induced phenotypic plasticity (Keller et al. 2013), although locomotor organs are obviously the target of natural selection (Bidau and Martínez 2018). Femur length may be positively associated with movement performance and dispersal potential in species (Whitman 2008). ...
Elevational gradients are closely associated with strong abiotic variation at small spatial scales and provide a powerful tool to assess species’ adjustments to climatic and other environmental factors. To understand the role of genetic underpinning and environmentally-induced plasticity on body size, we compared variation in a range of morphological traits in wild-caught and lab-reared (F1 generation) dark bush-crickets (Pholidoptera griseoaptera) from 10 populations sampled along an elevational gradient of approximately 1100 m. We used linear mixed models (LMM) and linear models to test the effects of sex, rearing environment (wild-caught vs. lab-reared), elevation and population identity, and the interactions between these factors on trait variation. In LMM, population identity was used as a random effect to test for trait inter-population repeatability. In the lab, we found genetically-based differences between populations; however, this variation wasn’t elevation-dependent, suggesting that it’s not locally adapted to elevation and associated environmental variables. In contrast, we observed a weak negative association between elevation and locomotor traits (hind femur length and hind tibia length), pronotum width and females’ ovipositor length in wild-caught bush-crickets, which could be attributable to environmentally-induced phenotypic plasticity. Plasticity could also be responsible for lower differences between populations and lower repeatability within populations in the wild than in the lab environment, and larger body-size traits in wild-caught bush-crickets. The lower repeatability in wild populations can be explained by the greater temporal and spatial environmental heterogeneity in the wild compared to lab. Sex-specific morphological differences were more pronounced in the wild than in the laboratory. Since we can assume limited gene flow between populations of the species, we can conclude that other fitness-related traits are subject to selection and thus enable the broad elevational distribution of this bush-cricket.
... better locomotion on the water's surface) rather than sexual selection (Klingenberg & Zimmermann, 1992;Tseng & Rowe, 1999). Allometric scaling of locomotory traits can also be ontogenetically constrained and thus result in a taxon exhibiting a particular allometry despite the net selection operating on the trait (Bidau & Martıńez, 2018). In this study, I use the Japanese beetle (Popillia japonica Newman) (Coleoptera; Scarabaeidae) to test predictions of how locomotory traits -legs and wings -in males and females should scale allometrically based on the sexually selective regime to which they are exposed. ...
... My findings suggest that the viability selection operating on these traits might be stronger than sexual selection and thus the observed allometric patterns are an outcome of this net selection. Alternatively, the patterns of static allometry detected here could be due to a common ancestral developmental program (see Bidau & Martıńez 2018). overwhelmed in both sexes by antagonistic viability selection on front leg size. ...
... Addressing the role of viability selection in allometric scaling will require measuring the strength and form of natural selection acting on the legs of P. japonica. It is also possible that leg size is constrained in P. japonica by nonfunctional factors such as gas exchange (Kaiser et al., 2007) or phylogeny (Bidau & Martıńez, 2018). ...
Evolutionary biologists have long posited that secondary sexual characters experiencing positive directional selection
should be positively allometric. Support for this hypothesis, however, is limited and appears to hold under a specific set of conditions. An alternative hypothesis argues that different forms of sexual selection can produce similar patterns of allometry, and vice versa, depending on the net effect of sexual selection and viability selection. We currently lack a general understanding of how particular patterns of allometry emerge from particular sexual selection regimes. Here, I empirically examine whether patterns of static allometry exhibited by leg and wing traits in female and male Japanese beetles (Popillia japonica) align with the form of sexual selection underlying them. Contrary to expectation, I found that patterns of allometry did not universally align with their regime of sexual selection. Despite the direction and strength of sexual selection differing between the sexes, I found that all traits were negatively allometric with the exception of tibia width in males, which was isometric. Patterns of allometry for tibia length and wing traits were sexually dimorphic under some conditions and the slopes for wing traits were steeper in mated than in unmated males. My results support the hypothesis that different sexual selection regimes can produce similar patterns of static allometry and suggest that viability selection on these traits might be stronger than sexual selection and could thus be responsible for shaping their patterns of static allometry.
... Thanks to their versatile jumping, walking, flying and chirping behavior, several Orthopteran species are classical models in functional morphology and biomechanics, including descriptive allometry (Huber et al. 1989, Fielding and DeFoliart 2008, Moradian and Walker 2008, Whitman 2008, Schöneich and Hedwig 2017, Bidau and Martínez 2018. Therefore, the biomechanics of jumping has been intensively studied, and it has been shown that based on biomechanical realities, natural selection would favor relatively longer legs in smaller species to compensate for the diminished jumping performance (Burrows 2010, Sutton andBurrows 2008). ...
... So far, both supporting and falsifying evidence has been obtained on the matter in various insect species (Espadaler and Gómez 2001;Farji-Brener et al. 2004;Kaspari and Weiser 1999;Parr et al. 2003;Schöning et al. 2005). Recently, Bidau and Martínez (2018) found the evolutionary allometry of hind femur length with respect to body length to be negative for about 1500 Orthopteran species, thus supporting the biomechanical approach to leg length in orthopterans. However, they also noted that if the biomechanical hypothesis were to be the main functional constraint, then the static and ontogenetic allometries would also be negative in any individual orthopteran species. ...
... In this article, the interrelationship of static, ontogenetic and evolutionary allometry of the third hind femur was investigated for the first time in Orthoptera. Interestingly, the ontogenetic allometry of hind femur length with respect to both body length and head width in the cricket G. bimaculatus was clearly linear and isometric or slightly positive and not negative as reported for the evolutionary allometry across Orthopterans in general or Gryllidae in particular (Bidau and Martínez 2018). The result follows the only other similar comparison in hemimetabolous insects by Klingenberg and Zimmermann (1992), who noted that the evolutionary allometry in the water strider genera Gerris and Aquaticus was markedly different from both static and ontogenetic allometries. ...
The evolution of morphological allometry or scaling is a long-standing enigma in biology. Three types of allometric relationships have been defined: static, ontogenetic and evolutionary allometry. However, the theory of the interrelationship between these three types of allometry have not been tested in Orthopterans and to a lesser extent in hemimetabolous insects. Here, the ontogenetic allometry of hind femur length in the cricket Gryllus bimaculatus was observed to be slightly positive as compared with a negative allometric relationship for Orthopterans in general, while the instar-specific static allometries were highly variable. The findings give support for the size-grain hypothesis in Orthoptera and indicate that ontogenetic allometries may not predict evolutionary allometries. The current model for the developmental basis of allometry derived from holometabolous insects is extended into a phylogenetic context and the potential of G. bimaculatus and other Orthopterans for further experiments of evo-devo of morphological scaling is discussed.
... Pélabon et al., 2013;Freidline et al., 2015), and evolutionary allometry is the study of the correlated rates of growth between the means of populations or species (e.g. Anzai et al., 2017;Bidau & Martínez, 2018). Variation in selection pressures and genetic constraints usually configure the evolutionary allometric relationships between body regions (Tidière et al., 2017). ...
Allometry determines relevant modifications in metazoan morphology and biology and is affected by many different factors, such as ontogenetic constraints and natural selection. A linear mixed model approach and reduced major axis regression were used to explore evolutionary interspecific allometric trends between the total trunk length and the lengths of the segments and spines in the phylum Kinorhyncha at three taxonomic levels: the whole phylum, the class and the family. Statistically significant results were found in all the trunk segments, meaning that these body units grow proportionally correlated with the body, contrary to the results obtained for the spines. Developmental and morphophysiological constraints could lead to negative allometry in the first and last segments, because these body regions in kinorhynchs are essential to the implementation of some of the main biological functions, such as feeding and locomotion. The differential arrangement of cuticular appendages between the taxonomic groups considered seems to cause different evolutionary trends, because positive allometry may appear if a segment requires more space to accommodate a large number of organs and appendages, and vice versa. The presence of sexual dimorphism could also define positive allometry of a segment, owing to the need to harbour the sexually dimorphic appendages and their associated structures.
... Given the lack of a large consensus phylogeny, a valid alternative are mixed-effect models using hierarchical taxonomic categories as random intercept effects. Linear mixed effect models have proven to be the most valid alternative in macroecological studies of fishes (Bunnefeld and Phillimore 2012, Luiz et al. 2012 and others organisms (Horne et al. 2015, Bidau andMartínez 2018). ...
The energetic demand of consumers increases with body size and temperature. This implies that energetic constraints may limit the trophic position of larger consumers, which is expected to be lower in tropical than in temperate regions to compensate for energy limitation. Using a global dataset of 3,635 marine and freshwater ray‐finned fish species, we addressed if and how climate affects the fish body size‐trophic position relationship in both freshwater and marine ecosystems, while controlling for the effects of taxonomic affiliation. We observed significant fish body size‐trophic position relationships for different ecosystems. However, only in freshwater systems larger tropical fish presented a significantly lower trophic position than their temperate counterparts. Climate did not affect the fish body size‐trophic position relationship in marine systems. Our results suggest that larger tropical freshwater fish may compensate for higher energetic constraints feeding at lower trophic positions, compared to their temperate counterparts of similar body size. The lower latitudinal temperature range in marine ecosystems and/or their larger ecosystem size may attenuate and/or compensate for the energy limitation of larger marine fish. Based on our results, temperature may determine macroecological patterns of aquatic food webs, but its effect is contingent on ecosystem type. We suggest that freshwater ecosystems may be more sensitive to warming‐induced alterations in food web topology and food chain length than marine ecosystems.
This article is protected by copyright. All rights reserved.
... Thirdly, a mixed linear model was conducted using the four explanatory variables. Phylogenetic autocorrelation was controlled in all models by including taxonomic ranks as a nested random factor (Amiel, Tingley, & Shine 2011;Olalla-Tárraga et al. 2011;Horne, Hirst, & Atkinson 2015;Bidau & Martínez 2018). This method has recently been shown to be a valid alternative in comparative studies of fishes, given the scarcity of robust phylogenetic hypotheses (Luiz et al. 2013). ...
... In the absence of a phylogenetic tree, we compensated for this possible limitation taking into account the hierarchical taxonomic organization to include the phylogenetic relatedness among species in the model (Gittleman & Luh 1992). Using a phylogeny is always preferable to using taxonomic structure, but in complex groups such as ray-finned fishes, where a robust phylogeny encompassing a good proportion of the existing species is unavailable, using a nested taxonomy is a valid alternative (Gittleman & Kot 1990;Luiz et al. 2013;Horne et al. 2015;Bidau & Martínez 2018). ...
Understanding the interspecific variation in body size across macroclimatic gradients has been of paramount importance to naturalists and biogeographers. Bergmann's rule, which describes a trend of increasing body size polewards, is arguably the best-known ecogeographical rule in terrestrial environments but remains largely unexplored in the marine realm. In this study we tested Bergmann's rule in marine ray-finned fishes (Pisces, Actinopterygii), analyzing the relationship between body size and latitude in 5662 species. To examine possible underlying mechanisms, we adopted a cross-species approach to evaluate the association of body size with four predictors: Sea Surface Temperature, Net Primary Productivity, Salinity, and Human impact. We analyzed the relationships between body size and environmental and anthropogenic variables building mixed linear models, which considered the taxonomic structure in the data. We conducted complementary analyses dividing the data into five latitudinal bands. Actinopterygii showed a clear Bergmannian pattern, with the largest species observed in temperate regions, being the first global analysis on ray-finned fishes showing a pattern consistent with Bergmann's rule. Sea Surface Temperature and Net Primary Productivity were the best predictors, in accordance with the time to sexual maturity and resource availability hypotheses. Our analyses based on latitudinal bands showed a differential response of body size to the environment, with temperature, salinity and human impact more strongly associated with size variation at cold environments. These results agree with previous studies on Bergmann's rule for terrestrial ectothermic, freshwater and marine fishes. Our findings suggest that temperature rise in the ocean and growing human impact may have effects on the distribution of body size, thus altering ecosystem functioning. Fundamental differences often assumed to exist between marine and terrestrial systems are not so evidently reflected in the emergence of large-scale body size gradients.
High trait variability among insects reflects a combination of intra- and inter-phenotype variations. Our aim was to assess if the trait distribution of body measurements can be more significantly influenced by sex (intraspecific variance) or by species (interspecific variance). To achieve this, we collected in Namibia tettigoniids belonging to two congeneric species of armoured ground crickets: Acanthoplus discoidalis (a significant pest in African croplands)
and the long-legged Acanthoplus longipes. We measured in the field the total body length, the maximal pronotal width and length, and the femur and tibia lengths of the hind legs in 106 adults. We also derived the body mass from length and width values of the sampled
specimens. No significant differences emerged in the two species by sex. A discriminant analysis clearly shows that at species level the locomotory traits as captured by tibia and femur lengths and the size traits as captured by body and pronotal lengths account for 99 % of the total variance and clearly separate this pest from its congeneric species. In essence, it is not primarily the body size that differentiates the two species, but rather the pronotum and hind leg larger sizes ofA. longipes. Different eco-ethological requirements, like the peculiarity
of the calling song and the movements within the vegetation (and the consequently needed energy), independently force these functional traits.
