Morphology of the male reproductive system of the social wasp, Polistes versicolor versicolor, with phylogenetic implications

Abstract

Variation in the morphology of the adult male reproductive system among different groups of Hymenoptera offer characteristics that help studies of behavior and the evolutionary history of this group. The objective of this study was to describe the adult male reproductive system of the wasp Polistes versicolor versicolor Olivier (Vespidae: Polistini). The reproductive systems were dissected, fixed and embedded for light microscopy. In P. v. versicolor, the reproductive system includes a pair of testes, each one with three fusiform follicles. From each follicle emerges an efferent duct that later join together, forming a deferent duct. The first half of the deferent duct is enlarged and differentiated into a region specialized for sperm storage, the seminal vesicle. At the post-vesicular region of each of the deferent ducts an accessory gland emerges. The seminal vesicle and the accessory gland are covered with a capsule forming a vesicle-gland complex, also observed in some species of North American Polistes. Sperm are released from testes in bundles, which are disorganized inside seminal vesicles. In the testicular follicles, 95 spermatozoa were observed per cyst on average.