Survey of morphological structures on male scape of Aphelinus

Aphelinus (Hymenoptera: Chalcidoidea) is a parasitic wasp genus that has strong ties to biological control programs for control of aphids. Upon observing Aphelinus specimens for morphological data for phylogenetic analyses, it was observed that the arrangement and structure of glandular systems on the ventral side of the scape of males differ within species groups. This study examined the morphological structures on the male scape across species groups in Aphelinus using scanning electron microscopy (SEM) imaging. Eight different collecting series from seven different species across six species groups were used. The specimens were critically point dried, gold sputter coated, and imaged using a Tescan Vega 3 SEM microscope. It was found that among the species examined, variation of the scape structures does exist in a variety of ways including height, number, and position. Also, the area where these structures are present also vary (protuberance vs. depression). This preliminary survey of the gland structures indicates that, taken together, they could be diagnostic for the species groups of Aphelinus. This also suggests that they may be useful in phylogenetic inferences, as they could have broad phylogenetic signal across the genus. The survey also provides information for species-level taxonomic decisions in the genus. The use of transmission electron microscopy (TEM) to investigate glandular properties further will also be discussed.