Pterometric Studies on Pannonian Drosophilidae - Wing Proportions and Phylogeny

The wing venation of 30 Pannonian species of the dipteran family Drosophilidae was analysed comparatively. 23 vein branching, origin and edge points were selected and used to determine 54 distances per wing. A scaling to the total wing length was carried out, and then the data of 130 wings, whose assignment to species and sex was known, were compared multivariate using principal component analysis. The relationship between species similarity in wing proportions and phylogenetic position was analysed for different Drosophilidae evolutionary hypotheses. Furthermore, we analysed how the wing proportions shift along the first two principal axes (PC1 and PC2). All species of the subfamily Steganinae show positive PC1 values, which means that within this family the proximal wing area is relatively extended compared to the rest of the wing. This is probably the original condition in the family. In the Drosophilinae genera Drosophila (ad partem), Hirtodrosophila, Scaptomyza and Chymomyza the PC1 values are negative and accordingly the wing base is relatively small. The genus Drosophila is divided into three clusters, the first consists of representatives of the melanogaster species group (subgenus Sophophora), but also includes Scaptodrosophila species. The second contains mainly species of the obscura species group (also Sophophora), but also D. suzukii, which belongs to the melanogaster species group, and D. busckii from the Dorsilopha subgenus. The two clusters most closely resemble the genus Chymomyza, while the third is similar to Scaptomyza. This third cluster contains species of the subgenus Drosophila and the genus Hirtodrosophila. Within the cluster, D. testacea and the quinaria species group are more similar to each other, D. hydei as a representative of the repleta species group lies somewhat apart. In many respects there is more agreement with the phylogenetic hypotheses of Throgmorton 1975 than with the current taxonomy of the Drosophilidae. In the genera Gitona, Chymomyza and the subgenus Sophophora, the distal wing segment is enlarged at the expense of the medial one (PC2).