Evolution of glandular structures on the scape of males in the genus Aphelinus Dalman (Hymenoptera, Aphelinidae)

Abstract

The pores and associated glands on male antennae in species of Hymenoptera are involved in mate recognition and are diverse and widespread among taxa. However, nothing has been published about these structures in species ofAphelinus(Chalcidoidea: Aphelinidae), a genus of parasitoid wasps with a long history in biological control. Images from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) ofAphelinus varipesrevealed pores on the ventral side of the male scape that were connected to glands. A survey of the scapes of male antennae in 16 species in six species complexes ofAphelinus, as well as two outgroup species,Aphytis melinusandCentrodorasp., showed that pores were present in all exceptCentrodorasp. The pores varied in several characters: the shape of the structures that carried them, pore size, elevation of the cuticle surrounding the structures, the extent of a carina delimiting the area around the structures, and the number and position of pores. The shape of the pore-bearing structures, the elevation of cuticle around these structures, and the extent of the carina around them map well onto a molecular phylogeny of theseAphelinusspecies. Combinations of pore characters are diagnostic of species complexes, and in some cases, species ofAphelinus.