Forewing Shape Research Articles

Geometric Morphometrics and Genetic Diversity Analysis of Chalcidoidea (Diglyphus and Pachyneuron) at Various Elevations.

Eulophidae and Pteromalidae are parasitic wasps with a global distribution and import for the biological control of pests. They can be distributed in different altitude regions, but their morphological and genetic adaptations to different altitudes are unclear. Here, we collected specimens that belong to Eulophidae and Pteromalidae from various altitudinal gradients, based on integrated taxonomic approaches to determine the species composition, and we analyzed their body shape and size from different altitudes using geometric morphometrics. Then, we performed an analysis of the D. isaea population's haplotype genes to illustrate their genetic diversity. As a result, eight species that belong to two genera, Diglyphus Walker (Eulophidae) and Pachyneuron Walker (Pteromalidae), were identified, including two newly recorded species from China (D. chabrias and D. sabulosus). Through a geometric morphometrics analysis of body shape, we found that a narrow forewing shape and a widened thorax are the significant characteristics of adaptation to high-altitude environments in D. isaea and P. aphidis. Additionally, the body size studies showed a principal relationship between centroid size and altitude; the size of the forewings and thorax increases at higher altitudes. Next, using haplotype analysis, 32 haplotypes were found in seven geographic populations with high genetic diversity of this species. Our research provides preliminary evidence for the morphological and genetic diversity adaptation of parasitic wasps to extreme environments, and these data can provide important references for investigations on the ecological adaptability of parasitic wasps.

Size and Shape Differences in Fore Wings of Honey Bee (Apis Mellifera) Queens, Workers and Drones

Abstract The three honey bee phenotypes - queens, workers, and drones differ in the size and shape of body parts. We used a large dataset to describe how the three phenotypes differed with regard to fore wings and applied the methodology of geometric morphometrics to measure the wings using the coordinates of nineteen landmarks. On average, queens had wings larger than workers, but the two castes had a broad overlap. Drones, on the other hand, had distinctly larger wings. Wing shape differed markedly among queens, workers and drones and can be used to reliably differentiate them from one other. Surprisingly, the fore wing shape of workers was more similar to that of drones than to that of queens. Small queens were not more similar to workers than large queens, and large workers were not more similar to queens than small workers. Because wing size, unlike body mass, does not change over the life of the queen, it can be used to evaluate the quality of a queen throughout its life and not only during a short period after emergence. We provide a large number of wing images of queens and drones, which can be used as a reference in future studies.

Got milkweed? Genetic assimilation as potential source for the evolution of nonmigratory monarch butterfly wing shape.

Monarch butterflies (Danaus plexippus) are well studied for their annual long-distance migration from as far north as Canada to their overwintering grounds in Central Mexico. At the end of the cold season, monarchs start to repopulate North America through short-distance migration over the course of multiple generations. Interestingly, some populations in various tropical and subtropical islands do not migrate and exhibit heritable differences in wing shape and size, most likely an adaptation to island life. Less is known about forewing differences between long- and short-distance migrants in relation to island populations. Given their different migratory behaviors, we hypothesized that these differences would be reflected in wing morphology. To test this, we analyzed forewing shape and size of three different groups: nonmigratory, lesser migratory (migrate short-distances), and migratory (migrate long-distances) individuals. Significant differences in shape appear in all groups using geometric morphometrics. As variation found between migratory and lesser migrants has been shown to be caused by phenotypic plasticity, and lesser migrants develop intermediate forewing shapes between migratory and nonmigratory individuals, we suggest that genetic assimilation might be an important mechanism to explain the heritable variation found between migratory and nonmigratory populations. Additionally, our research confirms previous studies which show that forewing size is significantly smaller in nonmigratory populations when compared to both migratory phenotypes. Finally, we found sexual dimorphism in forewing shape in all three groups, but for size in nonmigratory populations only. This might have been caused by reduced constraints on forewing size in nonmigratory populations.

Wing morphology and eyespot pattern of Erebia medusa (Lepidoptera, Nymphalidae) vary along an elevation gradient in the Carpathian Mountains

Wing morphology and eyespot pattern of Erebia medusa (Lepidoptera, Nymphalidae) vary along an elevation gradient in the Carpathian Mountains

The first Sharephemeridae (Insecta: Ephemeroptera) from the Jurassic Shiti Formation of South China

ABSTRACT The new genus and species, Jurassephemera zhangi gen. et sp. nov., belonging to the extinct family Sharephemeridae (Ephemeroptera: Mesephemeroidea), is established from the late Early Jurassic interval of the Shiti Formation of Guangxi Zhuang Autonomous Region, South China. The new genus and species is characterised by its moderate size; small head with reduced compound eyes; body with ten abdominal segments; round-triangular forewing shape; vein R dividing three times, forming five veinlets and three triads; veins MA, MP, and CuA straight, all basally forking once with single triads between; crossveins well developed; and hind wing oval, much smaller than forewing, with veins generally radial and single. SEM observations also reveal that crossveins are much more developed than previously recognised under optical illumination. The forewing venation of all sharephemerid genera is compared. The first report of this family in China herein increases the diversity and palaeogeographic distribution of Sharephemeridae.

Hidden Phylogenomic Signal Helps Elucidate Arsenurine Silkmoth Phylogeny and the Evolution of Body Size and Wing Shape Trade-Offs.

One of the key objectives in biological research is understanding how evolutionary processes have produced Earth's diversity. A critical step toward revealing these processes is an investigation of evolutionary tradeoffs-that is, the opposing pressures of multiple selective forces. For millennia, nocturnal moths have had to balance successful flight, as they search for mates or host plants, with evading bat predators. However, the potential for evolutionary trade-offs between wing shape and body size are poorly understood. In this study, we used phylogenomics and geometric morphometrics to examine the evolution of wing shape in the wild silkmoth subfamily Arsenurinae (Saturniidae) and evaluate potential evolutionary relationships between body size and wing shape. The phylogeny was inferred based on 782 loci from target capture data of 42 arsenurine species representing all 10 recognized genera. After detecting in our data one of the most vexing problems in phylogenetic inference-a region of a tree that possesses short branches and no "support" for relationships (i.e., a polytomy), we looked for hidden phylogenomic signal (i.e., inspecting differing phylogenetic inferences, alternative support values, quartets, and phylogenetic networks) to better illuminate the most probable generic relationships within the subfamily. We found there are putative evolutionary trade-offs between wing shape, body size, and the interaction of fore- and hindwing (HW) shape. Namely, body size tends to decrease with increasing HW length but increases as forewing (FW) shape becomes more complex. Additionally, the type of HW (i.e., tail or no tail) a lineage possesses has a significant effect on the complexity of FW shape. We outline possible selective forces driving the complex HW shapes that make Arsenurinae, and silkmoths as a whole, so charismatic. [Anchored hybrid enrichment; Arsenurinae; geometric morphometrics; Lepidoptera; phylogenomics; Saturniidae.].

The development of shape. Modular control of growth in the lepidopteran forewing.

The mechanisms by which tissues and organs achieve their final size and shape during development are largely unknown. Although we have learned much about the mechanisms that control growth, little is known about how those play out to achieve a structure's specific final size and shape. The wings of insects are attractive systems for the study of the control of morphogenesis, because they are perfectly flat and two-dimensional, composed of two closely appressed cellular monolayers in which morphogenetic processes can be easily visualized. The wings of Lepidoptera arise from imaginal disks whose structure is always perfectly congruent with that of the adult wing, so that it is possible to fate-map corresponding positions on the larval disk to those of the adult wing. Here we show that the forewing imaginal disks of Junonia coenia are subdivided into four domains, with characteristic patterns of expression of known patterning genes Spalt (Sal), Engrailed (En), and Cubitus interruptus (Ci). We show that DNA and protein synthesis, as well as mitoses, are spatially patterned in a domain-specific way. Knockdown of Sal and En using produced domain-specific reductions in the shape of the forewing. Knockdown of signaling pathways involved in the regulation of growth likewise altered the shape of the forewing in a domain-specific way. Our results reveal a multi-level regulation of forewing shape involving hormones and growth-regulating genes.

Mimicry: just wing it. Wing shape comparison between a mimicking swallowtail and its toxic model

Abstract Female eastern tiger swallowtails (Papilio glaucus) are well-known wing coloration mimics of the toxic pipevine swallowtail (Battus philenor). Given that forewing shape is an important component of butterfly flight behaviour found in unpalatable species, we hypothesized that the mimicking females also mimic the forewing shape of their poisonous model. Thus, we predicted that mimicking eastern tiger swallowtails have a more similar wing shape to their model compared with their non-mimicking conspecific morphs. In order to test this, we compared the forewing of the model with mimicking and non-mimicking eastern tiger swallowtail morphs using a standard geometric morphometrics approach. Contrary to our hypothesis, we found significant differences of forewing shape between the two species, with no overlap, regardless of the morph. However, mimicking and non-mimicking female eastern tiger swallowtails were significantly different from each other in wing shape. This indicates that either pleiotropic effects, possibly owing to wing coloration mimicry, or selection for different flight patterns in mimics informed the evolution of forewings in this species. Additionally, we found sexual dimorphism in forewing shape within each species, which supports research indicating that both sexual selection and sex-specific natural selection are important drivers in wing shape evolution.

Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria

Abstract. Abed F, Bachir-Bouiadjra B, Dahloum L, Yakubu A, Haddad A, Homrani A. 2021. Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria. Biodiversitas 22: 154-164. Honey bees play an important role as pollinators of many crops. Thus they are collectively considered as a veritable economic source. The present study was undertaken to describe variation in the right forewing geometry in two Algerian honeybee subspecies Apis mellifera intermissa and Apis mellifera sahariensis using landmark-based geometric morphometrics. A total of 1286 honeybees were sampled from 12 provinces in the northwest of Algeria. The forewing geometry was evaluated using 20 homologous landmarks by applying Procrustes superimposition analysis. The top four principal components accounted for only 41.1% of wing shape variation between the two subspecies. There was a significant difference in wing shape between the two subspecies (Mahalanobis distance = 1.0626 ; P<0.001), whereas their wing size seemed similar (P>0.05). Regarding the allometric effect, the percentage of variation in wing shape explained by size changes was relatively small, with 1.28% and 4.37% for A. m. intermissa and A.m sahariensis, respectively. The cross-validation procedure correctly classified 68.3% of specimens into their original groups. PERMANOVA test revealed significant differences in the right forewing shape among all geographic areas studied (P<0.001). The results clearly showed that the landmark-based geometric approach applied to forewings venation is a powerful and reliable tool in the discrimination of native honey bee subspecies and should be considered in local honey bee biodiversity improvement and conservation initiatives.

Radiation exposure causes developmental alterations in size and shape of wings and structures associated with song production in male crickets (Acheta domesticus)

AbstractEnvironmental disasters and growth of nuclear power contribute to increasing levels of radiation pollution in the biosphere. Major impacts concern development, fertility, and survivorship in diverse species. Subtle impacts are less appreciated even though they may have profound effects on individuals and populations. Here, we examined radiation impacts on male crickets, Acheta domesticus (L.) (Orthoptera: Gryllidae), specific to wing development. Alterations in global wing morphology are detectable, but this is a flightless species. However, mating success of males is highly dependent on specialized courtship songs generated by structures associated with the opposing forewings. Such signals identify males as both conspecific and ‘attractive/fit’ mates. Highly specialized structures found on male forewings include the chord, harp, mirror, plectrum, and file. These work in concert to generate the species‐specific male courtship song. Even slight alterations in wing morphology can alter these signals, and variation may also vary acoustic signals among populations. Here, we analyze the impacts of early‐life radiation exposure (0–10 Gy) on male forewing shape and size using morphometric analysis. A canonical variate analysis (CVA) illustrated that wing shape was significantly altered in a dose‐dependent basis: 10 Gy (P<0.0001), 7 Gy (P<0.0001), and 2 Gy (P = 0.0001). Principal component (PC) analysis as well as the CVA indicated that most variation in wing structure was associated with the mirror, one of the two main resonating regions on the forewing. Analysis of centroid size found significant reductions with 7 and 10 Gy radiation exposures. Significant radiation‐induced increases in fluctuating asymmetry were also detected, with fluctuating asymmetry values increasing with dose. Due to the known specialized nature of song‐producing structures and its association with both courtship songs and mating, it is likely that the alterations observed in shape and size will have larger impacts on male reproductive success. We are currently quantifying this and analyzing recordings of song structure to detect and characterize specific alterations by radiation.

Wing morphological responses to latitude and colonisation in a range expanding butterfly.

Populations undergoing rapid climate-driven range expansion experience distinct selection regimes dominated both by increased dispersal at the leading edges and steep environmental gradients. Characterisation of traits associated with such expansions provides insight into the selection pressures and evolutionary constraints that shape demographic and evolutionary responses. Here we investigate patterns in three components of wing morphology (size, shape, colour) often linked to dispersal ability and thermoregulation, along latitudinal gradients of range expansion in the Speckled Wood butterfly (Pararge aegeria) in Britain (two regions of expansion in England and Scotland). We measured 774 males from 54 sites spanning 799 km with a 10-year mean average temperature gradient of 4 °C. A geometric morphometric method was used to investigate variation in size and shape of forewings and hindwings; colour, pattern, and contrast of the wings were examined using a measure of lightness (inverse degree of melanism). Overall, wing size increased with latitude by ∼2% per 100 km, consistent with Bergmann’s rule. Forewings became more rounded and hindwings more elongated with history of colonisation, possibly reflecting selection for increased dispersal ability. Contrary to thermal melanism expectations, wing colour was lighter where larvae developed at cooler temperatures and unrelated to long-term temperature. Changes in wing spot pattern were also detected. High heterogeneity in variance among sites for all of the traits studied may reflect evolutionary time-lags and genetic drift due to colonisation of new habitats. Our study suggests that temperature-sensitive plastic responses for size and colour interact with selection for dispersal traits (wing size and shape). Whilst the plastic and evolutionary responses may in some cases act antagonistically, the rapid expansion of P. aegeria implies an overall reinforcing effect between these two mechanisms.

On the taxonomic position of the genera Krundia, Breukoscelis, and Uphodato(Hemiptera, Auchenorrhyncha, Fulgoroidea) described from the Insect Limestone of the Isle of Wight.

Three fossil genera, Krundia Szwedo, 2019, Breukoscelis Szwedo, 2019, and Uphodato Szwedo, 2019, described in the family Issidae are transferred to other families according to the shape and venation of forewings. Krundia Szwedo is transferred to the family Tropiduchidae. Breukoscelis Szwedo is placed in synonymy under Uphodato Szwedo and transferred to the family Cixiidae. Forewing venation of the members of Issidae, Tropiduchidae, and Cixiidae are discussed and illustrated.

Phylogeny of Libellulidae (Odonata: Anisoptera): comparison of molecular and morphology-based phylogenies based on wing morphology and migration.

BackgroundEstablishing the species limits and resolving phylogenetic relationships are primary goals of taxonomists and evolutionary biologists. At present, a controversial question is about interspecific phylogenetic information in morphological features. Are the interspecific relationships established based on genetic information consistent with the traditional classification system? To address these problems, this study analyzed the wing shape structure of 10 species of Libellulidae, explored the relationship between wing shape and dragonfly behavior and living habits, and established an interspecific morphological relationship tree based on wing shape data. By analyzing the sequences of mitochondrial COI gene and the nuclear genes 18S, 28S rRNA and ITS in 10 species of dragonflies, the interspecific relationship was established.MethodThe wing shape information of the male forewings and hindwings was obtained by the geometric morphometrics method. The inter-species wing shape relationship was obtained by principal component analysis (PCA) in MorphoJ1.06 software. The inter-species wing shape relationship tree was obtained by cluster analysis (UPGMA) using Mesquite 3.2 software. The COI, 18S, ITS and 28S genes of 10 species dragonfly were blasted and processed by BioEdit v6 software. The Maximum Likelihood(ML) tree was established by raxmlGUI1.5b2 software. The Bayes inference (BI) tree was established by MrBayes 3.2.6 in Geneious software.ResultsThe main difference in forewings among the 10 species of dragonfly was the apical, radial and discoidal regions dominated by the wing nodus. In contrast, the main difference among the hindwings was the apical and anal regions dominated by the wing nodus. The change in wing shape was closely related to the ability of dragonfly to migrate. The interspecific relationship based on molecular data showed that the species of Orthetrum genus branched independently of the other species. Compared to the molecular tree of 10 species, the wing shape clustering showed some phylogenetic information on the forewing shape (with large differences on the forewing shape tree vs. molecular tree), and there was no interspecific phylogenetic information of the hindwing shape tree vs. molecular tree.ConclusionThe dragonfly wing shape characteristics are closely related to its migration ability. Species with strong ability to migrate have the forewing shape that is longer and narrower, and have larger anal region, whereas the species that prefer short-distance hovering or standing still for a long time have forewing that are wider and shorter, and the anal region is smaller. Integrating morphological and molecular data to evaluate the relationship among dragonfly species shows there is some interspecific phylogenetic information in the forewing shape and none in the hindwing shape. The forewing and hindwing of dragonflies exhibit an inconsistent pattern of morphological changes in different species.

Molecular and morphometric identification of pistachio psyllids with niche modeling of Agonoscena pistaciae (Hemiptera: Aphalaridae).

Species of Agonoscena (Hemiptera: Aphalaridae) are key pests of pistachio in all of the most important pistachio producing countries in the Old World. The efficiency and accuracy of DNA barcoding for the identification of Agonoscena species were tested using mitochondrial cytochrome c oxidase subunit 1 (mtCO1) and cytochrome b (cytb) gene sequences. Moreover, morphometric sexual dimorphism was studied. Finally, the potential geographical distribution of Agonoscena pistaciae, the most important pistachio pest, was calculated using the MaxEnt model. Similar relationships of clustering were found in the morphometric analysis and the molecular analyses with mtCO1 and cytb genes, with A. bimaculata and A. pistaciae being closely related, and A. pegani constituting their sister group. Although the results showed that the cytb gene is a better marker for barcoding in this group, the mtCO1 gene clearly separates the three psyllid species making mtCO1 suitable for diagnostic purposes. A geometric morphometric analysis showed that the distance between landmark number 7 (bifurcation of vein M) to the fore margin of the forewing, and the distance between landmarks number 6 (apex of vein Cu1b) and 11 (wing base), are the most important geometric characters for diagnosing the studied species. Moreover, the forewing shape of males vs females is similar in A. pistaciae and A. bimaculata but differs significantly in A. pegani. In the ecological niche modeling of the distribution of A. pistaciae, the most important contribution was made by the variable 'minimum temperature of coldest period'. The most suitable areas for A. pistaciae are restricted to Eastern, Southern and some parts of Central Iran.

Resolving the taxonomic status of biocontrol agents belonging to the Aphidius eadyi species group (Hymenoptera: Braconidae: Aphidiinae): an integrative approach.

Species that belong to the Aphidius eadyi group have been used as biocontrol agents against Acyrthosiphon pisum worldwide. However, despite their extensive use, there are still gaps in our knowledge about their taxonomy and distribution. In this study, we employed an integrative taxonomic approach by combining genetic analyses (mtDNA COI barcoding) with standard morphological analyses and geometric morphometrics of forewing shape. We identified three species within the A. eadyi species group, viz., A. smithi, A. eadyi and A. banksae. Genetic separation of all three species was confirmed, with mean genetic distances between species ranging from 5 to 7.4%. The following morphological characters were determined as the most important for separating species of the A. eadyi group: number and shape of costulae on the anterolateral part of the petiole, shape of the central areola on the propodeum, and shape and venation of the forewings. The differences in wing shape of all three species were statistically significant, but with some overlapping. We identified A. banksae as a widely distributed pea aphid parasitoid, whose known range covers most of the western Palaearctic (from the UK to Israel). Aphidius banksae is diagnosed and redescribed.

Revision of the European Lysiphlebus species (Hymenoptera: Braconidae: Aphidiinae) on the basis of COI and 28SD2 molecular markers and morphology

Members of the genus Lysiphlebus Foerster are medium-sized endoparasitoid aphidiine wasps with over 30 species distributed worldwide. They attack numerous aphid hosts, and some species are important biological control agents. All European Lysiphlebus species are revised based on sequence information from the mitochondrial COI barcoding gene and the nuclear 28SD2 gene, morphological traits, and on information about their host specificity. The taxonomic status of 13 European Lysiphlebus species is confirmed, while 11 are redescribed and illustrated. The following four Lysiphlebus species are synonymized: L. melandriicola Starý, 1961 = L. fabarum (Marshall, 1896), L. hirtus Starý, 1985 (= L. confusus Tremblay & Eady, 1978), L. hispanus Starý, 1973 (= L. desertorum Starý, 1965), and L. safavii Starý, 1985 (= L. hirticornis Mackauer, 1960). Two new Lysiphlebus species are described: L. volkli sp.n. and L. brachycaudi sp.n. Our results, based on both COI and 28SD2, confirm the existence of three monophyletic species groups within the genus: (1) the ‘fabarum’ group, which includes L. fabarum, L. cardui (Marshall, 1896), L. confusus, L. hirticornis, L. brachycaudi sp.n., and L. volkli sp.n.; (2) the ‘testaceipes’ group, which includes L. testaceipes (Cresson, 1880), L. orientalis Starý & Rakhshani, 2010, L. fritzmuelleri Mackauer, 1960, L. balcanicus Starý, 1998, L. desertorum, and probably L. dissolutus (Nees, 1811); and (3) the ‘alpinus’ group, consisting solely of L. alpinus Starý, 1971. Geometric morphometrics of fore wing shape proved to be a powerful tool to delineate sibling species within the ‘fabarum’ group. We were able to confirm for the first time sexual lines of L. cardui and L. confusus. Furthermore, an additional potentially asexual Lysiphlebus taxon in Europe is revealed based on the discovery of an asexual line of L. volkli sp.n. in Iran. An illustrated key for identification of the European Lysiphlebus species is provided.

Geomorphic Morphometric Differences between Populations ofSpeyeria diana(Lepidoptera: Nymphalidae)

The wing shape of butterflies can be used as a character to measure individual butterfly and population-level differences in adult forms. We conducted a geometric morphometric analysis of wing shape for Speyeria diana (Cramer & Stoll 1777) (Lepidoptera: Nymphalidae), a species currently threatened by extirpation across portions of its range. We photographed and digitized 243 pinned S. diana specimens from natural history museums in North America and Europe to compare wing shape and size across the historical and current distribution. We used principal components analysis (PCA) to compare variation in landmarks on forewings and hind wings. We used the principal component scores in a multiple analysis of variance (MANOVA) to test for differences, and interactions, between male and female specimens, eastern and western specimens, low and high elevation specimens, and specimens collected before and after 1950. We found significant differences between wing shape in male and female specimens, with male forewings being narrower and more elongated, possibly making them well suited for patrolling behavior. Female forewings were more rounded and wider, possibly reflecting their life history, because much of their life is spent on the forest floor in search of oviposition sites. We found significant regional differences in male forewing shape, reflecting the long-term geographic and genetic separation between these groups. We also found significant differences in female forewing shape between low and high elevation sites. Speyeria diana female forewings from high elevation populations were narrower than low elevation populations, indicating that these females may be more mobile than those from low elevations with wider forewings. There were no effects of yr since capture of specimens. The wing shape of western populations of S. diana appears to be adapted for low dispersal, supporting other recent findings that also indicate western populations of S. diana are both spatially and genetically isolated. We conclude that the future of S. diana will require the thoughtful preservation of well-connected high elevation habitats, especially in the western distribution where dispersal is more limited than in the east.

Evolutionary pattern of the forewing shape in the Neotropical genus of jumping plant-lice (Hemiptera: Psylloidea: Russelliana)

Geometric morphometric and phylogenetic analyses, applied to 43 species of Russelliana, shed light on the evolution of insect wing shape. Unconstrained and constrained ordination techniques are introduced to detect patterns of the forewing shape variation within genus. Results show a high congruence between forewing shape variation and host-plant preference supporting monophyly of most phylogenetic groups in Russelliana. Reconstruction of the ancestral forewing state shows its similarity to a forewing shape of Solanaceae feeding species defined as ancestors by the phylogenetic study supporting a hypothesis as to a primary association of Russelliana with Solanaceae. In contrast to some other comparative studies on insect wing shape, results of the present study reveal a strong correlation between variation of forewing shape in Russelliana and its phylogeny. Potential influence of vicariant events and host shifts on the evolution of forewing shape is discussed.

Morphological discrimination of the genera Binodoxys Mackauer and Trioxys Haliday (Hymenoptera: Braconidae: Aphidiinae) based on the general shape of forewings.

The genera Binodoxys and Trioxys , members of the Aphidiinae subfamily, are classified in the same tribe Trioxini and the subtribe Trioxina. These two genera are morphologically very similar but differ ecologically. Generally, Binodoxys species are specialized in parasitizing aphids on herbaceous plants unlike Trioxys species which have co-evolved with the tree attacking aphids. For this study 80 right forewings of four Binodoxys and two Trioxys species were analyzed using the geometric morphometrics method. The sixteen specific landmarks were digitalized on each wing and the results demonstrated statistically significant differences of wing shape between the genera. By visualizing using the CVA method, the wing structure that was the most variable was the radial sector vein – which is much shorter in Binodoxys than in Trioxys species.

Morphological variation of Aphidius ervi Haliday (Hymenoptera: Braconidae) associated with different aphid hosts.

BackgroundParasitoids are frequently used in biological control due to the fact that they are considered host specific and highly efficient at attacking their hosts. As they spend a significant part of their life cycle within their hosts, feeding habits and life history of their host can promote specialization via host-race formation (sequential radiation). The specialized host races from different hosts can vary morphologically, behaviorally and genetically. However, these variations are sometimes inconspicuous and require more powerful tools in order to detect variation such as geometric morphometrics analysis.MethodsWe examined Aphidius ervi, an important introduced biological control agent in Chile associated with a great number of aphid species, which are exploiting different plant hosts and habitats. Several combinations (biotypes) of parasitoids with various aphid/host plant combinations were analyzed in order to obtain measures of forewing shape and size. To show the differences among defined biotypes, we chose 13 specific landmarks on each individual parasitoid wing. The analysis of allometric variation calculated in wing shape and size over centroid size (CS), revealed the allometric changes among biotypes collected from different hosts. To show all differences in shape of forewings, we made seven biotype pairs using an outline-based geometric morphometrics comparison.ResultsThe biotype A. pis_pea (Acyrthosiphon pisum on pea) was the extreme wing size in this study compared to the other analyzed biotypes. Aphid hosts have a significant influence in the morphological differentiation of the parasitoid forewing, splitting biotypes in two groups. The first group consisted of biotypes connected with Acyrthosiphon pisum on legumes, while the second group is composed of biotypes connected with aphids attacking cereals, with the exception of the R. pad_wheat (Rhopalosiphum padi on wheat) biotype. There was no significant effect of plant species on parasitoid wing size and shape.DiscussionAlthough previous studies have suggested that the genotype of parasitoids is of greater significance for the morphological variations of size and shape of wings, this study indicates that the aphid host on which A. ervi develops is the main factor to alter the structure of parasitoid forewings. Bigger aphid hosts implied longer and broader forewings of A. ervi.