A comparative morphology of the male genitalia of Aphididae (Insecta, Hemiptera): part 2

The present study provides new data related to the morphology of the male genitalia of Aphididae. The structure of the male genitalia of 39 species from 23 genera of Aphididae was studied using light and scanning electron microscopy. In the species studied, the genitalia of males consist of a phallus composed of the sclerotized basal part with its articulation and a membranous apical part—an aedeagus as well as parameres. This state probably represents the hypothetical plesiomorphic condition of the external male genitalia of aphids. According to the results of the present study, the male genitalia vary among subfamilies (the most varied in Lachninae). Both the phallus and parameres show great variability in their form and the number of setae and may provide characters of taxonomic and diagnostic importance. The shape, size, and modification of parameres are considered in conjunction with the phylogenetic relationships among the studied taxa. Compared with Lachninae, Greenideinae, Aiceoninae, the external genitalia of Aphidinae are less specialized, having many features in common with those of drepanosiphine aphids and differing little from the hypothetical condition. In dwarfish males of Anoeciinae, Thelaxinae, Hormaphidinae, and Eriosomatinae, the miniaturization of the body size affects on the modification of genitalia, mostly parameres. However, the homology of non-modified and modified structures of parameres is not clear.