Hind Wing Shape Evolves Faster than Front Wing Shape in Calopteryx Damselflies

Wing shape has been shown in a variety of species to be influenced by natural and sexual selection. In damselflies, front- and hind wings can beat independently, and functional differentiation may occur. Males of Calopteryx damselflies show species-specific nuptial flights that differ in colour signalling with the hind wings. Therefore, hind wing shape and colour may evolve in concert to improve colour display, independent of the front wings. We predicted that male hind wing shape evolves faster than front wing shape, due to sexual selection. Females do not engage in sexual displays, so we predicted that females do not show differences in divergence between front- and hind wing shape. We analysed the non-allometric component of wing shape of five European Calopteryx taxa using geometric morphometrics. We found a higher evolutionary divergence of hind wing shape in both sexes. Indeed, we found no significant differences in rate of evolution between the sexes, despite clear sex-specific differences in wing shape. We suggest that evolution of hind wing shape in males is accelerated by sexual selection on pre-copulatory displays and that this acceleration is reflected in females due to genetic correlations that somehow link the rates of wing shape evolution in the two sexes, but not the wing shapes themselves.     

The effects of latitude,body size,and sexual selection on wing shape in a damselfly

Under natural selection, wing shape is expected to evolve to optimize flight performance. However, other selective factors besides flight performance may influence wing shape. One such factor could be sexual selection in wing sexual ornaments, which may lead to alternative variations in wing shape that are not necessarily related to flight performance. In the present study, we investigated wing shape variations in a calopterygid damselfly along a latitudinal gradient using geometric morphometrics. Both sexes show wing pigmentation, which is a known signal trait at intra‐ and interspecific levels. Wing shape differed between sexes and, within the same sex, the shape of the hind wing differed from the front wing. Latitude and body size explained a high percentage of the variation in wing shape for female front and hind wings, and male front wings. In male hind wings, wing pigmentation explained a high amount of the variation in wing shape. On the other hand, the variation in shape explained by pigmentation was very low in females. We suggest that the conservative morphology of front wings is maintained by natural selection operating on flight performance, whereas the sex‐specific differences in hind wings most likely could be explained by sexual selection. The observed sexual dimorphism in wing shape is likely a result of different sex‐specific behaviours. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 263–274.     

Wing pigmentation in territorial male damselflies, Calopteryx haemorrhoidalis: a possible relation to sexual selection

One striking characteristic in adult males of some odonate species is the presence of wing pigmentation. In Calopteryx species, males show a series of pre- and postcopulatory behavioural displays during which they face females while showing their pigmented wings. One hypothesis to explain the precopulatory flying displays and the associated wing pigmentation is that they may serve a sexual selection function. I investigated this in the territorial damselfly Calopteryx haemorrhoidalis. Males of this species defend aquatic substrates that females use for oviposition. Observational evidence indicated that males with a higher proportion of wing pigmentation were more likely to defend a territory, obtained more matings, had fewer gut parasites, survived in the study site and stayed in territories for longer. Experimental evidence suggested that the relationship mating success and wing pigmentation still held when controlling for the size of the substrate defended by territorial males. Similar to other studies in the Calopterygidae, these results suggest that wing pigmentation may be favoured by sexual selection. I discuss, however, whether an alternative function for male copulatory courtship displays and wing pigmentation, as sexual and/or species recognition, may also explain the evolution of these traits. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Evolutionary patterns of hind wing morphology in dung beetles (Coleoptera: Scarabaeinae)

The shape of wings can be a good predictor of adaptations to different selective pressures and the value of wing features in taxonomy and phylogeny has long been recognized. In our investigation of the hind wing evolution of dung beetles (Scarabaeinae) we use geometric morphometrics combined with a cladistic approach. The variations of entire hind wings and of three specific regions of 80 dung beetle species were investigated using 19 landmarks and outline data. Extensive evidence indicates that the wing as a whole and the three separate regions were under different selective pressures. The detailed evolutionary patterns of the three regions and the reconstruction of the ancestral forms were computed by mapping the geometric morphometrics data onto a tree based on a cladistic character analysis.     

Co-evolving wing spots and mating displays are genetically separable traits in Drosophila

The evolution of sexual traits often involves correlated changes in morphology and behavior. For example, in Drosophila, divergent mating displays are often accompanied by divergent pigment patterns. To better understand how such traits co-evolve, we investigated the genetic basis of correlated divergence in wing pigmentation and mating display between the sibling species Drosophila elegans and Drosophila gunungcola. Drosophila elegans males have an area of black pigment on their wings known as a wing spot and appear to display this spot to females by extending their wings laterally during courtship. By contrast, D. gunungcola lost both of these traits. Using Multiplexed Shotgun Genotyping (MSG), we identified a ∼440 kb region on the X chromosome that behaves like a genetic switch controlling the presence or absence of male-specific wing spots. This region includes the candidate gene optomotor-blind (omb), which plays a critical role in patterning the Drosophila wing. The genetic basis of divergent wing display is more complex, with at least two loci on the X chromosome and two loci on autosomes contributing to its evolution. Introgressing the X-linked region affecting wing spot development from D. gunungcola into D. elegans reduced pigmentation in the wing spots but did not affect the wing display, indicating that these are genetically separable traits. Consistent with this observation, broader sampling of wild D. gunungcola populations confirmed that the wing spot and wing display are evolving independently: some D. gunungcola males performed wing displays similar to D. elegans despite lacking wing spots. These data suggest that correlated selection pressures rather than physical linkage or pleiotropy are responsible for the coevolution of these morphological and behavioral traits. They also suggest that the change in morphology evolved prior to the change in behavior.     

Beyond the wing planform: morphological differentiation between migratory and nonmigratory dragonfly species

Migration is a significant trait of the animal kingdom that can impose a strong selective pressure on several structures to overcome the amount of energy that the organism invests in this particular behaviour. Wing linear dimensions and planform have been a traditional focus in the study of flying migratory species; however, other traits could also influence aerodynamic performance. We studied the differences in several flight‐related traits of migratory and nonmigratory Libellulid species in a phylogenetic context to assess their response to migratory behaviour. Wings were compared by linear measurements, shape, surface corrugations and microtrichia number. Thorax size and pilosity were also compared. Migratory species have larger and smoother wings, a larger anal lobe that is reached through an expansion of the discoidal region, and longer and denser thoracic pilosity. These differences might favour gliding as an energy‐saving displacement strategy. Most of the changes were identified in the hind wings. No differences were observed for the thorax linear dimensions, wetted aspect ratio, some wing corrugations or the wing microtrichiae number. Similar changes in the hind wing are present in clades where migration evolved. Our results emphasize that adaptations to migration through flight may extend to characteristics beyond the wing planform and that some wing characteristics in libellulids converge in response to migratory habits, whereas other closely related structures remain virtually unchanged. Additionally, we concluded that despite a close functional association and similar selective pressures on a structure, significant differences in the magnitude of the response may be present in its components.     

Sexual Dimorphism in Sturnira lilium (Chiroptera,Phyllostomidae): Can Pregnancy and Pup Carrying Be Responsible for Differences in Wing Shape?

Competition is one of the most cited mechanisms to explain secondary sexual dimorphism in animals. Nonetheless, it has been proposed that sexual dimorphism in bat wings is also a result of adaptive pressures to compensate additional weight caused by fetus or pup carrying during the reproductive period of females. The main objective of this study is to verify the existence of sexual dimorphism in Sturnira lilium wings. We employed geometric morphometrics techniques using anatomical landmarks superimposition to obtain size (Centroid Size) and shape variables of wings, which were reduced by Linear Discriminant Analysis (LDA). We also employed classical morphometrics using wing length measurements to compare efficiency between these two morphometric approaches and make comparisons using wing area measurements. LDA indicated significant differences between wing shapes of males and females, with 91% (stepwise classification) and 80% (leave-one-out cross validation) of correct classification. However, the size variable obtained did not contribute to such classifications. We have observed larger areas in female wings, but we found no differences in wing length measurements and no allometric effects in wing length, shape and area measurements. Interestingly, our study has provided evidences of morphological differences where classical morphometrics have failed. LDA and area measurements analyses revealed that females have a different area distribution in distinct portions of the wing, with wider dactylopatagia and plagiopatagia, and wingtips more triangular than males. No differences in body length or relative wing length were observed between the sexes, but pregnant females have more body weight than non-pregnant females and males. Our findings suggest that sexual dimorphism in the wing shape of S. lilium is probably related to the increase in flight efficiency of females during reproductive period. It decreases wing loading in specific portions of the wing and reduces energy cost to maintain a faster and maneuverable flight.     

Drivers of wing shape in a widespread Neotropical bird: a dual role of sex-specific and migration-related functions

A large body of research has shown how avian morphology is shaped by specific behavioral repertoires and life history traits. Yet, the majority of such research has been conducted on birds breeding at north-temperate latitudes. We tested the hypothesis that functional wing traits of Fork-tailed Flycatchers (Tyrannus savana), which migrate within South America, vary predictably between non-migratory and migratory flycatchers. Additionally, due to sex-specific differences in this species (e.g., males perform courtship displays), we explored sex-related variation in wing shape. We applied classic measures of wing shape (e.g., wing loading, length, aspect ratio, pointedness), as well as landmark-based morphometric analysis to describe the wing morphology of Fork-tailed Flycatchers from breeding populations across South America. We found that migratory flycatchers tend to have more pointed wings than non-migratory flycatchers. Additionally, we found that males have wings that are significantly longer, more pointed, with a higher aspect ratio and that are more swept than those of females, regardless of whether they migrate or not. Overall, our results suggest that wing shape of Fork-tailed Flycatchers is the result of a complex set of tradeoffs shaped by selective pressures exerted on both sexes (i.e., the need to forage on the wing, evade predators and migrate efficiently), as well as sex-specific behaviors (e.g., the need for males to execute acrobatic displays).     

Morpho morphometrics: Shared ancestry and selection drive the evolution of wing size and shape in Morpho butterflies

Butterfly wings harbor highly diverse phenotypes and are involved in many functions. Wing size and shape result from interactions between adaptive processes, phylogenetic history, and developmental constraints, which are complex to disentangle. Here, we focus on the genus Morpho (Nymphalidae: Satyrinae, 30 species), which presents a high diversity of sizes, shapes, and color patterns. First, we generate a comprehensive molecular phylogeny of these 30 species. Next, using 911 collection specimens, we quantify the variation of wing size and shape across species, to assess the importance of shared ancestry, microhabitat use, and sexual selection in the evolution of the wings. While accounting for phylogenetic and allometric effects, we detect a significant difference in wing shape but not size among microhabitats. Fore and hindwings covary at the individual and species levels, and the covariation differs among microhabitats. However, the microhabitat structure in covariation disappears when phylogenetic relationships are taken into account. Our results demonstrate that microhabitat has driven wing shape evolution, although it has not strongly affected forewing and hindwing integration. We also found that sexual dimorphism of forewing shape and color pattern are coupled, suggesting a common selective force.     

Wing pigmentation in Calopteryx damselflies: a role in thermoregulation?

Body melanization may show adaptive variation related to thermoregulation ability, and it is to be expected that the degree of melanization will change among populations or closely related species across environmental gradients of solar radiation and/or environmental temperature. Some melanized secondary sexual traits may also play a role in sexual selection, leading to interpopulation variation, which would not be predicted by thermoregulation pressures alone. We studied the relationships between the interpopulation variation in wing pigmentation level (i.e. melanized secondary sexual trait) of two closely related species of Calopteryx damselfly, and both solar radiation and maximum environmental temperature estimates. Wing pigmentation differs between these species, is gender specific and is used in species' discrimination. Only Calopteryx virgo meridionalis males showed a significant negative partial correlation between wing pigmentation degree and temperature. However, C. virgo meridionalis females showed a positive significant partial correlation between wing pigmentation degree and solar radiation. Wing pigmentation in Calopteryx xanthostoma males was not related to solar radiation or temperature. Thus, thermoregulation pressures poorly explained the observed variations in wing pigmentation between populations, although they might have an adaptive significance at the species' level. As wing pigmentation showed important latitudinal variation, several other selection pressures which might act on melanized traits are briefly discussed. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 36–44.     

Adaptive evolution of butterfly wing shape: from morphology to behaviour

Butterflies display extreme variation in wing shape associated with tremendous ecological diversity. Disentangling the role of neutral versus adaptive processes in wing shape diversification remains a challenge for evolutionary biologists. Ascertaining how natural selection influences wing shape evolution requires both functional studies linking morphology to flight performance, and ecological investigations linking performance in the wild with fitness. However, direct links between morphological variation and fitness have rarely been established. The functional morphology of butterfly flight has been investigated but selective forces acting on flight behaviour and associated wing shape have received less attention. Here, we attempt to estimate the ecological relevance of morpho‐functional links established through biomechanical studies in order to understand the evolution of butterfly wing morphology. We survey the evidence for natural and sexual selection driving wing shape evolution in butterflies, and discuss how our functional knowledge may allow identification of the selective forces involved, at both the macro‐ and micro‐evolutionary scales. Our review shows that although correlations between wing shape variation and ecological factors have been established at the macro‐evolutionary level, the underlying selective pressures often remain unclear. We identify the need to investigate flight behaviour in relevant ecological contexts to detect variation in fitness‐related traits. Identifying the selective regime then should guide experimental studies towards the relevant estimates of flight performance. Habitat, predators and sex‐specific behaviours are likely to be major selective forces acting on wing shape evolution in butterflies. Some striking cases of morphological divergence driven by contrasting ecology involve both wing and body morphology, indicating that their interactions should be included in future studies investigating co‐evolution between morphology and flight behaviour.     

Morphological correlates of migratory distance and flight display in the avian genus Anthus

Conflicting pressures on the evolution of wing morphology are exemplified within the avian genus Anthus , where different migratory and flight display behaviours might be expected to exert different effects on the evolution of wing morphology. A phylogenetically controlled study of wing shape in relation to migratory distance and flight display suggests that migration has a larger impact on wing morphology than does flight display, despite the fact that flight display is generally the more heavily used flight-type. Correlations between single measures of morphology and migration were found only in males, although principal components analysis suggests that overall wing shape is correlated with migratory distance in both sexes. With regard to flight display, males, but not females, show a positive relationship between flight display type and the length of a flight feather that is highly elongated relative to other flight feathers. This exceptionally long flight feather is also found in other genera that perform flight displays.     

Evolution of wing pigmentation in Drosophila: Diversity,physiological regulation,and cis-regulatory evolution

Fruit flies (Drosophila and its close relatives, or “drosophilids”) are a group that includes an important model organism, Drosophila melanogaster, and also very diverse species distributed worldwide. Many of these species have black or brown pigmentation patterns on their wings, and have been used as material for evo-devo research. Pigmentation patterns are thought to have evolved rapidly compared with body plans or body shapes; hence they are advantageous model systems for studying evolutionary gains of traits and parallel evolution. Various groups of drosophilids, including genus Idiomyia (Hawaiian Drosophila), have a variety of pigmentations, ranging from simple black pigmentations around crossveins to a single antero-distal spot and a more complex mottled pattern. Pigmentation patterns are sometimes obviously used for sexual displays; however, in some cases they may have other functions. The process of wing formation in Drosophila, the general mechanism of pigmentation formation, and the transport of substances necessary for pigmentation, including melanin precursors, through wing veins are summarized here. Lastly, the evolution of the expression of genes regulating pigmentation patterns, the role of cis-regulatory regions, and the conditions required for the evolutionary emergence of pigmentation patterns are discussed. Future prospects for research on the evolution of wing pigmentation pattern formation in drosophilids are presented, particularly from the point of view of how they compare with other studies of the evolution of new traits.     

果蝇Drosophila biarmipes翅斑二型性的生态学意义(英文)

雌性对雄性表饰的偏好性有利于性别选择。目前尚不清楚这一偏好性是否只限于雄性表饰或这一偏好性实际上是源于影响后代适合度的基因。对于雄性可直接有利于雌性或其后代适合度的交配系统而言,答案是肯定的--雌性偏好于与对气候胁迫具有更强生理抗性的雄性交配。对果蝇Drosophila biarmipes 的室内研究已经证明了求偶过程中翅斑的作用,但是其生态学意义仍然不清楚。我们检验了有翅斑与无翅斑雄性果蝇D. biarmipes 及雌性偏好的雄性所产生的后代对环境胁迫的抗性是否不同。结果表明：在干燥或冷胁迫条件下,有翅斑的雄性果蝇比无翅斑的雄性果蝇的交配成功率明显要高。相反,在高湿条件下,无翅斑雄性果蝇的交配频率更高。我们也发现在较为干旱的条件下,与有翅斑雄性交配的雌性果蝇的生殖力以及所得后代从卵至成虫的存活率更高。我们的结果与优良基因性选择假说一致,说明交配选择能给雌性带来间接好处。这是对热带物种D. biarmipes翅色二型性生态学意义的首次报道。     

Structural Characteristics of Allomyrina Dichotoma Beetle＇s Hind Wings for Flapping Wing Micro Air Vehicle

In this study, we present a complete structural analysis ofAllomyrina dichotoma beetle＇s hind wings by investigating their static and dynamic characteristics. The wing was subjected to the static loading to determine its overall flexural stiffness. Dy- namic characteristics such as natural frequency, mode shape, and damping ratio of vibration modes in the operating frequency range were determined using a Bruel ＆ Kjaer fast Fourier transform analyzer along with a laser sensor. The static and dynamic characteristics of natural Allomyrina dichotoma beetle＇s hind wings were compared to those of a fabricated artificial wing. The results indicate that natural frequencies of the natural wing were significantly correlated to the wing surface area density that was defined as the wing mass divided by the hind wing surface area. Moreover, the bending behaviors of the natural wing and artificial wing were similar to that of a cantilever beam. Furthermore, the flexural stiffness of the artificial wing was a little higher than that of the natural one whereas the natural frequency of the natural wing was close to that of the artificial wing. These results provide important information for the biomimetic design of insect-scale artificial wings, with which highly ma- neuverable and efficient micro air vehicles can be designed.     

Evolutionary directional asymmetry and shape variation in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae): an example using hind wings

The western corn rootworm Diabrotica virgifera virgifera LeConte is a pest of maize in the USA and Europe and especially a problem in particular regions of Croatia. In the present study, patterns of variation in hind wing shape were examined. The first objective was to examine the influence of soil type on 10 populations of D. v. virgifera sampled from three regions in Croatia that differed according to edaphic factors and climate. The second objective was to investigate the potential evolutionary presence of directional asymmetry on hind wings. Geometric morphometrics was used to examine these objectives by quantifying the morphological variation within and among individuals and populations. Overall, D. v. virgifera hind wing shape changed according to major soil type classifications in Croatia. The three hind wing morphotypes found varied because of basal radial vein differences, related to landmarks 1, 3, 7, and 14. The findings of the present study show that hind wing shape in D. v. virgifera can be used to differentiate populations based on edaphic factors and may have application as a monitoring tool in the integrated management of D. v. virgifera. In an evolutionary context, the presence of directional asymmetry in the hind wings of D. v. virgifera adds to the ever growing data on the evolution of insect wings. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 110–118.     

Intercontinental effect on sexual shape dimorphism and allometric relationships in the beetle pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae)

Hind wing shape variation was examined in 686 adult Diabrotica virgifera virgifera collected from maize plants in Europe and the USA Corn Belt, using geometric morphometric techniques. Sexual dimorphism at an Intercontinental scale was assessed using canonical variates analysis, a multivariate statistical method used to find the shape characters that best distinguish among groups of specimens. Our results showed that each of the populations of D. v. virgifera investigated in this study showed high levels of sex based hind wing shape dimorphism. In particular a stronger and more obvious pattern of hind wing shape variation was found in the USA than in Europe. These results support previous studies on D. v. virgifera wing shape that show that female D. v. virgifera have more elongated wings than males. These differences raise the question of whether sexual dimorphism may be modulated by natural selection.     

Imitating the initial evolutionary stage of a tail ornament

Abstract.— Costs of a sexual ornament in its early evolutionary form and the relationship between these costs and individual condition may be an important influence in the likelihood of possible evolutionary mechanisms involved in the evolution of this ornament. We reconstructed the tail shape in hypothetical ancestors of recent hirundines (Aves: Hirundinidae), from which the elongation of tail feathers under sexual selection might have begun. By elongating the tail in sand martins ( Riparia riparia , Hirundinidae), we simulated the early evolution of a long forked tail–the typical ornament of male hirundines. Birds with initial ornament captured smaller insects than controls, which suggests that this ornament imposed a cost in terms of impaired foraging. Furthermore, birds with naturally longer tails were better able to cope with initial ornament than naturally short-tailed birds. If length of tail in sand martins indicates the quality of individuals, our results suggest higher costs of this initial ornament for poorer than for higher quality individuals. We discuss the potential role of the handicap principle and other mechanisms in early evolution of a tail ornament.     

The Role of Wing Pigmentation, UV and Fluorescence as Signals in a Neotropical Damselfly

Pigmentation patterns, ultraviolet reflection and fluorescent emission are often involved in mate recognition and mate quality functions in many animal taxa. We investigated the role of wing ultra-violet reflection, fluorescence emission, and pigmentation on age and sexual signals in the damselfly Mnesarete pudica. In this species, wings are sexually dimorphic in colour and exhibit age dependency: males and females show a smoky black colouration when young, turning red in mature males while it turns brown in females. First, we investigated wing UV patterns through reflectance and emission spectra. Second, behavioural experiments were undertaken to show male and female responses to manipulated wing pigmentation and experimentally reduced UV (UV-). Reflectance spectra of the wings of juvenile and mature males and females were used to show the differences between controls and individuals with manipulated colouration used in the behavioural experiment. UV-reduced, females with wings painted red, and control males and females were tethered and presented to conspecific males and females, and their behavioral responses were recorded. The male red wing pigmentation and females with red wings elicited an aggressive response in territorial males and a sexual response in females. Both males and females showed neutral responses towards individuals with reduced UV. Wing signals of juvenile individuals also provoked neutral responses. These results suggest that UV, together with pigmentation, plays a role during mate recognition in males and females. Other than butterflies and spiders, it seems that fluorescence signals and UV reflectance can also be part of communication in odonates.     

Do dung beetles show interrelated evolutionary trends in wing morphology,flight biomechanics and habitat preference?

In flying organisms, wing shape and biomechanical properties are recognized as key traits related to dispersal, foraging behavior, sexual selection and habitat preferences. To determine if differences in dung beetle wing shape and flight biomechanics are consistent with habitat preferences in a phylogenetic context, we examined how wing morphology varied in a set of 18 Mozambique forest and grassland dung beetle (Scarabaeinae) species, representing nine genera and six tribes. Geometric morphometric measurements were taken of entire wings, as well as two additional shape characters comprising the RA4 and CuA to J regions of veins. Ordination (Principal Components Analysis and Canonical Variate Analysis) of landmark data revealed three different trends in wing shape related to expansion or contraction in external wing margins. These trends were consistent with published dung beetle phylogenies and a phylogenetic reconstruction of ancestral morphological changes using parsimony analysis of wing landmark configurations. Analysis of variance showed that the Procrustes distances between wing shapes were significantly correlated to species identity (~?48% of variance), wing size (~?27%), habitat (~?11%) and two of the three, tested, biomechanical variables (wing loading, wing aspect ratio: ~?1%). However, while a phylogenetic generalized least squares analysis confirmed a strongly significant phylogenetic signal for wing shape, it found no significant effect of any other variable. Therefore, wing shape evolution in dung beetles appears to have been phylogenetically constrained and habitat may constitute only a weak selective pressure for changes in wing shape.