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

Abstract

The genera Binodoxys and Trioxys, members of the Aphidiinae subfamily, are classified in the same subtribe Trioxina within the tribe Trioxini. These two genera are morphologically very similar, but differ in a large degree in their ecology. 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, we analyzed the right forewings of four Binodoxys and two Trioxys species, using the method of geometric morphometrics. Sixteen specific landmarks were digitalized for each forewing of 80 parasitoid individuals. The results of two statistical methods ANOVA and MANOVA demonstrated statistically significant differences of the wing shapes, especially between the genera. Visualizing the results of the dispersion of specimens in the morphospace via multivariate tests PCA and CVA, we found that the most variable character in wing structure was the radial sector, differentiating Binodoxys from Trioxys.

Keywords

• Trioxina
• geometric morphometrics
• variability
• parasitoids