Male Wing Research Articles

EMS Mutagenesis in the Pea AphidAcyrthosiphon pisum

In aphids, clonal individuals can show distinct morphologic traits in response to environmental cues. Such phenotypic plasticity cannot be studied with classical genetic model organisms such as Caenorhabditis elegans or Drosophila melanogaster. The genetic basis of this biological process remain unknown, as mutations affecting this process are not available in aphids. Here, we describe a protocol to treat third-stage larvae with an alkylating mutagen, ethyl methanesulfonate (EMS), to generate random mutations within the Acyrthosiphon pisum genome. We found that even low concentrations of EMS were toxic for two genotypes of A. pisum. Mutagenesis efficiency was nevertheless assessed by estimating the occurrence of mutational events on the X chromosome. Indeed, any lethal mutation on the X-chromosome would kill males that are haploid on the X so that we used the proportion of males as an estimation of mutagenesis efficacy. We could assess a putative mutation rate of 0.4 per X-chromosome at 10 mM of EMS. We then applied this protocol to perform a small-scale mutagenesis on parthenogenetic individuals, which were screened for defects in their ability to produce sexual individuals in response to photoperiod shortening. We found one mutant line showing a reproducible altered photoperiodic response with a reduced production of males and the appearance of aberrant winged males (wing atrophy, alteration of legs morphology). This mutation appeared to be stable because it could be transmitted over several generations of parthenogenetic individuals. To our knowledge, this study represents the first example of an EMS-generated aphid mutant.

Male wing shape differs between condition-dependent alternative reproductive tactics in territorial damselflies

Territorial contests between males without weaponry are based on costly displays and can result in condition-dependent alternative reproductive tactics that maximize male fitness. Physiological and morphological traits such as fat content, body size or the expression of secondary sexual traits have been shown to contribute to male territory-holding potential. When territorial contests are based on flight displays, wing morphology is expected to contribute to the territory-holding potential of a male through its effects on flight performance. We explored whether wing shape contributed to the territory-holding potential of males of three species of Calopteryx damselflies. Males of these species show two distinct, condition-dependent behavioural tactics: territorial and nonterritorial. Previous studies have shown that territorial males have higher fitness than nonterritorial males. We used mark–recapture to determine male tactics within the populations and compared wing shape, size and wing coloured spot size (a secondary sexual trait) between tactics. Territorial males of all three species had shorter and slightly broader hindwings than nonterritorial males. In two species, forewings of territorial males were longer and broader than forewings of nonterritorial males. Wing size and wing spot size did not differ between tactics. We suggest that the wing shape of territorial males might confer better flight manoeuvrability, which would be advantageous for territorial contests. Therefore, wing shape is likely to be an important trait contributing to territory-holding potential in condition-dependent alternative reproductive tactics based on flight displays.

Does allometry of a sexually selected ornamental trait vary with sexual selection intensity? A multi‐species test in damselflies

Ornaments may show hyperallometry in certain taxa, i.e. large individuals have proportionally larger ornaments than small ones. One hypothesis suggests that higher sexual selection intensity leads to steeper hyperallometric patterns. This study tested whether an ornamental trait subject to both intra‐ and intersexual selection showed steeper allometric slopes than when subject solely to intrasexual selection. The study employed the sexually selected male wing pigmentation of 14 calopterygid species (damselflies) that differ in sexual selection intensity (intrasexual selection versus intra‐ and intersexual selection). Hyperallometry was not a uniform pattern in the study species. Furthermore, the allometric slopes did not differ between sexual selection intensities. The allometry of ornamental traits is therefore highly variable even among related species. Other selection pressures – probably species‐specific and at a local scale – acting on wing pigmentation might explain the diversity of allometric patterns.

Intralocus Sexual Conflict over Wing Length in a Wild Migratory Bird

Intralocus sexual conflict (ISC) occurs when males and females have different adaptive peaks but are constrained from evolving sexual dimorphism because of shared genes. Implications of this conflict on evolutionary dynamics in wild populations have not been investigated in detail. In comprehensive analyses of selection, heritability, and genetic correlations, we found evidence for an ISC over wing length, a key trait for flight performance and migration, in a long-term study of wild great reed warblers (Acrocephalus arundinaceus). We found moderate sexual dimorphism, high heritability, moderate sexually antagonistic selection, and strong positive cross-sex genetic correlation in wing length, together supporting the presence of ISC. A negative genetic correlation between male wing length and female fitness indicated that females inheriting alleles for longer wings from their male relatives also inherited lower fitness. Moreover, cross-sex genetic correlations imposed constraint on the predicted microevolutionary trajectory of wing length (based on selection gradients), especially in females where the predicted response was reversed. The degree of sexual dimorphism in wing length did not change over time, suggesting no sign of conflict resolution. Our study provides novel insight into how an ISC over a fitness trait can affect microevolution in a wild population under natural selection.

Shenahweum minutum (Hemiptera, Aphidoidea: Drepanosiphinae)-taxonomic position and description of sexuales.

The oviparous female and winged male of Shenahweum minutum (Davis) are described and illustrated in detail for the first time. Notes on distribution and host plants are presented as well as additional taxonomic data on the genus.

Odour influences whether females learn to prefer or to avoid wing patterns of male butterflies

Mating displays are often composed of multiple signals in multiple sensory modalities, with each individual signal contributing to the attractiveness of the displaying individual. Adult mate preferences for some of these signals are learned during premating, or juvenile, social experience with a sexually mature individual. While learned mate preferences have been described in multiple taxa, it is still unclear how the different display signals perceived during the learning period influence the development of adult mate preferences. Of particular interest is whether a learned mate preference for a sexual signal in one modality is context dependent (i.e. dependent on a second signal in either the same or a different sensory modality). Here we test whether a signal in one modality (odour) influences the interpretation (aversion or preference learning) of signals in a different modality (wing colour patterns) using the butterfly Bicyclus anynana. Previously we showed that female B. anynana learn to prefer additional ornaments, UV-reflective white spots, on the wings of males if they are exposed to these ornaments on the first day after eclosion from pupae. We now show that females exposed to males with manipulated odour do not learn to prefer these additional ornaments, and learn to avoid the wild-type male ornamentation. This aversion learning, where animals learn to avoid visual signals previously coupled with unattractive odours and to prefer visual signals previously coupled with attractive odours, demonstrates that visual mate preference learning in a butterfly is context dependent, and that specific sexual signals may have epistatic effects on mate preference development.

Primitive ants (Hymenoptera: Sphecomyrminae) in the Campanian (Late Cretaceous) of North Carolina (USA)

A small amber piece containing one nearly complete and four partial winged male fossil ants was collected from a lignite layer at a site along the Neuse River near Goldsboro, North Carolina, USA. Based on the anatomical details, these ants belong to the extinct subfamily Sphecomyrminae. While a formal species description and naming is not the purpose of this paper, similarities are noted to the ant genera Sphecomyrma and Baikurus, and taxonomic identification is made with the latter: Baikurus. This finding confirms the presence of the subfamily Sphecomyrminae in the Campanian stage and adds North Carolina to a short list of worldwide sites where Cretaceous ants have been uncovered. Further, this finding provides added confirmation of the social nature of ants already in the Late Cretaceous with particular reference to swarming behavior, as this piece is the fourth discovery of multiple winged males in amber.

Taxonomy of the genus Udara (Lepidoptera: Lycaenidae) in New Caledonia and the Wet Tropics of Australia, with a review of butterfly endemism in these regions

AbstractThe lycaenid genus Udara Toxopeus is recorded for the first time from New Caledonia where it is represented by the newly described species U. renevieri sp. nov. The species is figured, the male genitalia are illustrated, and the taxon is compared with U. cardia (C. Felder, 1860) (from Maluku through New Guinea to the Solomon Islands and Australia) to which it appears to be most closely related. The taxonomic status of U. cardia tenella syn. nov. and stat. nov. from the Wet Tropics biome of north‐east Australia is revised and treated as a subspecies of U. cardia based on comparative evidence of the morphology of the male genitalia and wing colour pattern elements. The holotypes of both Lycaena cardia C. Felder, 1860 and Lycaena tenella Miskin, 1891 are illustrated. Patterns of butterfly endemism in New Caledonia‐Loyalty Islands and the Wet Tropics are discussed in relation to the conservation importance of these biodiversity hot spots. Estimated levels of endemism are 21% for New Caledonia and 5% (17% if subspecies are included) for the rainforest component of the Wet Tropics.

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.

A new damsel-dragonfly from the Mesozoic of China with a hook-like male anal angle (Odonata: Isophlebioptera: Campterophlebiidae)

A new genus and species of campterophlebiid dragonfly, Angustiphlebia mirabilis gen. nov. et sp. nov., is described from the Jiulongshan Formation in China. It has some remarkable venational structures, i.e. a hypertrophy of the male hind wing anal angle, a quite long gaff, and a secondary branch of the anal anterior near subdiscoidal cell in hind wing, supporting the hypothesis of a sister-group relationship with the genus Oreophlebia. These new data will help to solve the phylogenetic relationships within the Campterophlebiidae.http://www.zoobank.org/urn:lsid:zoobank.org:pub:16E602E6-3567-44D7-BF64-95A6597E55DE

Preliminary study of wing interference patterns (WIPs) in some species of soft scale (Hemiptera, Sternorrhyncha, Coccoidea, Coccidae)

The fore wings of scale insect males possess reduced venation compared with other insects and the homologies of remaining veins are controversial. The hind wings are reduced to hamulohalterae. When adult males are prepared using the standard methods adopted to females and nymphs, i.e. using KOH to clear the specimens, the wings become damaged or deformed, an so these structures are not usually described or illustrated in publications. The present study used dry males belonging to seven species of the family Coccidae to check the presence of stable, structural colour patterns of the wings. The visibility of the wing interference patterns (WIP), discovered in Hymenoptera and Diptera species, is affected by the way the insects display their wings against various backgrounds with different light properties. This frequently occurring taxonomically specific pattern is caused by uneven membrane thickness and hair placement, and also is stabilized and reinforced by microstructures of the wing, such as membrane corrugations and the shape of cells. The semitransparent scale insect’s fore wings possess WIPs and they are taxonomically specific. It is very possible that WIPs will be an additional and helpful trait for the identification of species, which in case of males specimens is quite difficult, because recent coccidology is based almost entirely on the morphology of adult females.

Una nueva subespecie de <i>Heraclides androgeus</i> (Lepidoptera: Papilionidae) y sus aspectos biogeográficos

A new subspecies of Heraclides androgeus (Lepidoptera: Papilionidae) and its biogeographical aspects. Heraclides androgeus epidaurus was described and illustrated by Godman & Salvin in 1890 based on specimens obtained in Veracruz, indicating that their distribution encompassed both the Pacific and Atlantic sides of Mexico. Later authors commented that there were morphological differences between the male wings from both populations. We analyzed, described and nominated Heraclides androgeus reyesorum ssp. nov. Vargas, Llorente & Luis distributed in the Mexican Pacific coast, based on 62 specimens, and compared it with H a. epidaurus from the Gulf of Mexico, based on more than 200 specimens housed at UNAM: Museo de Zoología, Facultad de Ciencias and the Colección Nacional de Insectos of the Instituto de Biologia, as well as some collections from the USA. The main characters were the width of the yellow and black bands on forewings in males, which had a significant difference between the populations of both sides of Mexico, although some characters were variable and showed partial overlap. In the hindwings, the differences were the extent of the subterminal lunules in dorsal and ventral view. We also analyzed the male genitalia, finding notorious differences in both sclerotic processes of the harpe. Subspecific differences between females refer to the brightness and extent of green spots on the hindwings and the extent of lunules in the ventral view. The greatest abundance of H. a. reyesorum ssp. nov. was in the tropical deciduous forest, with gallery forest and in the lower range of the cloud forest, present at altitudes of 500-800 m and 1000-1 750 m, respectively. We discussed the pattern of endemism due to historical vicariant processes and explain the presence of the new subspecies of H. androgeus and other taxa of specific level.

Wing Characteristics and Spring Arrival Date in Barn SwallowsHirundo rustica

Flight morphology traits affect flight performance and energetic demands, and hence they are of special importance for migratory birds. It is believed that high wing aspect ratio (ratio of wing span squared to wing area) and low wing loading (ratio of body weight to wing area) both reduce the energetic costs of flight, thus allowing for enduring flight and fast migration. We addressed this topic in a four-year study on the Barn Swallow Hirundo rustica population near Warsaw, Central Poland. We hypothesized that individuals possessing wings with higher aspect ratio and lower loading should arrive at the breeding area earlier than other individuals, and that these individuals should be characterized by higher annual survival than the average individual. Male Barn Swallows arrived at the breeding ground on average earlier than females, and older birds arrived earlier than second year birds. Males with high aspect ratio wings arrived from Africa earlier than the average male, independent of age. There was no significant association between aspect ratio and arrival date in females. The relationship between male wing aspect ratio and arrival date remained significant when controlling for the effects of potential confounding variables (including the estimates of male phenotypic quality, body condition and body size). High aspect ratio wings may help male Barn Swallows migrate faster than the average male, and thus arrive at the breeding area earlier in spring and achieve the benefits of early arrival. However, the relationship was weak, explaining only 5% of the variation in male arrival date (age, and hence experience, explained 38% of the variance). Wing loading was significantly correlated with timing of arrival in both male and female Barn Swallows, with early arrivals being characterized by higher wing loading than later ones. This finding can be explained by the benefits of arrival at the breeding quarters with body reserves that should help copy with costs of early arrival. We found no significant relationship between wing area and timing of arrival. Furthermore, we found no evidence for wing aspect ratio and wing loading determining annual survival rate in the Barn Swallow.

Sexual traits are sensitive to genetic stress and predict extinction risk in the stalk-eyed fly, Diasemopsis meigenii.

The handicap principle predicts that sexual traits are more susceptible to inbreeding depression than nonsexual traits. However, this hypothesis has received little testing and results are inconsistent. We used 11 generations of full-sibling mating to test the effect of inbreeding on sexual and nonsexual traits in the stalk-eyed fly Diasemopsis meigenii. Consistent with the theoretical predictions, the male sexual trait (eyespan) decreased more than nonsexual traits (female eyespan and male wing length), even after controlling for body size variation. In addition, male eyespan was a reliable predictor of line extinction, unlike other nonsexual traits. After 11 generations, inbred lines were crossed to generate inbred and outbred families. All morphological traits were larger in outbred individuals than inbred individuals. This heterosis was greater in male eyespan than in male wing length, but not female eyespan. The elevated response in male eyespan to genetic stress mirrored the result found using environmental stress during larval development and suggests that common mechanisms underlie the patterns observed. Overall, these results support the hypothesis that male sexual traits suffer more from inbreeding depression than nonsexual traits and are in line with predictions based on the handicap principle.

Male wing color properties predict the size of nuptial gifts given during mating in the Pipevine Swallowtail butterfly (Battus philenor)

In many animals, males bear bright ornamental color patches that may signal both the direct and indirect benefits that a female might accrue from mating with him. Here we test whether male coloration in the Pipevine Swallowtail butterfly, Battus philenor, predicts two potential direct benefits for females: brief copulation duration and the quantity of materials the male passes to the female during mating. In this species, males have a bright iridescent blue field on the dorsal hindwing surface, while females have little or no dorsal iridescence. Females preferentially mate with males who display a bright and highly chromatic blue field on their dorsal hindwing. In this study, we show that the chroma of the blue field on the male dorsal hindwing and male body size (forewing length) significantly predict the mass of material or spermatophore that a male forms within the female's copulatory sac during mating. We also found that spermatophore mass correlated negatively with copulation duration, but that color variables did not significantly predict this potential direct benefit. These results suggest that females may enhance the material benefits they receive during mating by mating with males based on the coloration of their dorsal hindwing.

The influence of male wing shape on mating success in Drosophila melanogaster

Drosophila melanogaster males court females through a series of steps. In one of these steps, the male vibrates his wings to produce a courtship song that is species specific. Variation in the shape of Drosophila wings has been described among populations and species, but it is still unknown whether this variation influences the courtship process. In our laboratory, replicate strains were obtained from a natural population of D. melanogaster by artificial selection for rounded or elongated wing shapes. We used those strains and a nonselected strain to test the influence of wing shape on male mating success. We observed significantly higher success by males from strains with elongated wings when competing with those with rounded or nonselected wings, regardless of the female type. In addition, smaller males were more successful. We also recorded the courtship songs produced by males of different wing shape strains. We detected some variation among the courtship song produced by males depending on the original strain. However, this difference did not fully explain the success of males with elongated wings. Our results therefore show that wing shape has to be considered as influencing male mating success in Drosophila . • The wing shape can influence male mating success more than size in Drosophila . • More elongated wings confer advantage in the competition for mating. • The shape of the wings influences the courtship songs.

Origins of house reinfestation with Triatoma infestans after insecticide spraying in the Argentine Chaco using wing geometric morphometry

Identifying the origins of insect vectors collected after community-wide residual insecticide applications is a relevant challenge in the Gran Chaco region where the main vector of Chagas disease Triatoma infestans usually reinfests human dwellings. Wing geometric morphometry was used to compare the right wings of 63 males and 54 females collected at 4months post-spraying (MPS) with those from 165 males and 111 females collected before full-coverage spraying with pyrethroids in a well-defined rural area in Northeastern Argentina. Male and female wing centroid size resulted significantly larger at 4MPS than before interventions, but no significant changes in shape were detected. Metric disparity (variance of shape) varied significantly in males but not in females. Using shape variables, a relatively large fraction of post-spraying males (70%) and females (54%) could not be differentiated from those collected at the same source house or at the nearest infested house before interventions. Bugs collected at 4 and 8MPS in a persistently infested house were mainly assigned to the source house. These results support the hypothesis of persistent bug populations that survived the insecticide application at local spatial scales, and are consistent with the occurrence of vector control failures most likely related to moderate pyrethroid resistance. Wing geometric morphometry is a useful tool for identifying sources of reinfestation, but it is limited by the spatial structure found in the reference populations. Combined with field and genetic data, this approach may contribute to the understanding of the reinfestation process and improvement of vector control strategies.

Two lactones in the androconial scent of the lycaenid butterfly Celastrina argiolus ladonides

Male adult butterflies of many species have characteristic odors originating from the disseminating organs known as androconia. Despite the fact that androconia exist in several species, there have been few investigations on adult scents from the lycaenid species. Celastrina argiolus ladonides (Lycaenidae) is a common species in Eurasia. We have reported that male adults of this species emit a faint odor, and the major components causing this odor have been newly found in the Insecta. By using field-caught individuals, we determined the chemical nature and location of this odor in the butterfly. Gas chromatography-mass spectrometry (GC-MS) analyses revealed that two lactone compounds, lavender lactone and δ-decalactone, are present in the extracts of males but absent in those of the females. On an average, approximately 50 ng of each compound was found per male. Chiral GC analyses performed using enantiomerically pure standards revealed that the natural lavender lactone was a mixture of two enantiomers with an R/S ratio of 32:68, whereas the natural δ-decalactone contained only the R-enantiomer. When the analyses were conducted using different parts-forewings, hindwings, and body-of three males, the lactones were more abundantly found on the forewings and hindwings than on the body. Microscopic observation of the wings demonstrated that battledore scales known as androconia are scattered on the upper surface of both the wings of C. argiolus ladonides males. These results indicate that the specialized scales on the wings of males serve as scent-disseminating organs.

Visual and Olfactory Female-Borne Cues Evoke Male Courtship in the Aphid Parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae)

We investigated the courtship and mating behavior of the pan-tropical polyphagous endoparasitoid Aphidius colemani Viereck. The courtship and mating displays, the magnitude of male-male sexual approaches and the role of female-borne cues evoking male courtship behavior were quantified. The sequence of events leading to copulation in this parasitoid did not differ from that found for other braconids. Females refused to copulate more than once. Same-sex courtships were observed among males and their possible role in an adaptive context is discussed. Olfactory female-borne cues played a key role in eliciting the courtship responses of males. Males were attracted by freshly dead females, but not by dead females soaked in hexane, nor by visual cues from females alone. Intense male wing fanning behavior was elicited by crushed abdomens of virgin females, suggesting that the female abdomen is the source of a short-distance pheromone crucial in evoking male courtship. Further studies are required to clarify the exact nature of the chemicals involved.

The wing morphology of limnephilid caddisflies in relation to their habitat preferences

Summary The aerial dispersal of merolimnic insects is a prerequisite for maintaining metapopulations and for colonising new habitats. Flight morphology, as one determinant of dispersal capacity, may be related to the distribution patterns and ecological preferences of aquatic insects, but empirical data for Trichoptera are scarce. This study aimed to provide flight morphological data for common European Trichoptera species in relation to their ecological preferences. We measured the flight morphology of 26 Central European species of Limnephilidae (Trichoptera) including wing length, wing width, wing area, relative wing length and the aspect ratio of the fore and hind wings (combined). There were strong relationships between forewing length and body length (r² = 0.884), wing width (r² = 0.960) and wing area (r² = 0.93) in the untransformed data. Species of the same genus may differ strongly in wing length, wing width and wing area; however, when the wing area is considered on the size‐independent scale of relative wing length, species of the same genus are more similar. Sexual dimorphism was species specific. Male wing dimensions exceeded those of females in all species that displayed significant differences between the sexes except in Parachiona picicornis. For aerodynamic indices such as aspect ratio, only 28 % of the studied species show sexual dimorphism; in Limnephilus fuscicornis and Potamophylax luctuosus, males exceed females, and in Drusus annulatus, Drusus discolor and Potamophylax cingulatus, females exceeded males. On the basis of our data, we conclude that females may be the primary dispersers in four of the 18 species for which sufficient data were available, whereas in two species males appear to be stronger dispersers. We found three different morphological blueprints in forewing length and wing width: Group 1 encompassed crenal‐inhabiting species with a distinct habitat preference for mineral habitats (low aspect ratio, small wings; e.g. D. discolor); group 2 comprised rhithral species without a distinct habitat preference (high aspect ratio, large wings; e.g. P. cingulatus); and group 3 encompassed species inhabiting lentic waters and preferring organic habitats (high aspect ratio, medium‐sized wings; e.g. Anabolia nervosa).