Variation of wing shape in the Drosophila virilis species group (Diptera: Drosophilidae) |
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| Authors: | O A Bubliy K S Tcheslavskaia A M Kulikov O E Lazebny and V G Mitrofanov |
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| Institution: | Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia;;Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA;;Koltsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia |
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| Abstract: | Wing shape variation was analysed with geometric morphometric methods in 17 laboratory strains, representing 11 closely related species (including two subspecies) of the Drosophila virilis group: D. virilis, D. lummei, D. novamexicana, D. americana americana, D. americana texana, D. montana, D. lacicola, D. flavomontana, D. borealis, D. littoralis, D. ezoana and D. kanekoi. Overall shape estimated using Procrustes coordinates of 14 landmarks was highly variable among strains and very similar in females and males. The landmarks in the distal part of the wing showed higher variation across strains than those in the proximal part. Procrustes distances between species were not consistent with phylogenetic distances previously suggested for the virilis group. Moreover, Procrustes distances between strains within species and within two major phylads (virilis and montana) were comparable with those between species and between phylads, respectively. The most different from other members of the group was the endemic D. kanekoi species, currently viewed as separate subphylad within the montana phylad. Allometric effects were found to be partly responsible for shape differences between the strains. Three most significant shape transformations were considered using the relative warp analysis and the strains were ordinated in accordance with transformation values. The pattern of relative warp scores could be easily interpreted only for the third warp explaining about 13% of shape variation. It separated the largest species, D. montana, D. ezoana and D. kanekoi, from other ones and was mainly associated with shape changes in the proximal region of the wing. The results of the present work suggest that wing shape in the virilis species group is not related to the speciation process. The observed proximal‐distal contrasts and allometric effects are in agreement with data of other studies, in which wing shape variation was analysed within Drosophila species. |
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| Keywords: | Drosophila virilis group laboratory strains wing shape variation geometric morphometric methods |
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