Oocyte development in the primitively social wasp, Cerceris antipodes (Hymenoptera Sphecidae)

Abstract

Oocyte development and resorption were studied in females occupying single and multi-female nests in the sphecid wasp Cerceris antipodes Smith. Females had two polytrophic ovaries with three ovarioles in each. A maximum of one mature chorionated egg or two large developing oocytes was found in an individual. Most females were resorbing one or more terminal oocytes. About 90% of all females were inseminated. Some uninseminated females had large developing oocytes. Females collected outside of the October to March nesting season did not have large developing oocytes. Many females collected during the nesting season had a large developing oocyte. In all samples females that lacked a large developing oocyte and were resorbing most of their oocytes were found. No seasonal trend of oocyte development within the nesting season was obvious. Internal parasites were found in 4% of females and none of these females had a large developing oocyte. Females more than 10 days old were capable of developing a mature egg. There was no consistent correlation between age and the size of her largest developing oocyte in females more than 10 days old. There also was no consistent correlation between the size of a female and the size of her largest developing oocyte. However, within a nest, the oldest and largest females tended to have larger oocytes than their nestmates. There was no evidence that the presence of nestmates inhibited oocyte development, since females from single and multi-female nests had oocytes of similar size. Provisioners and nonprovisioners had oocytes of similar size. Individual nests represented a range of social types from eusocial to solitary. C. antipodes is a species with considerable variation in oocyte development among females, and therefore nests represented a variety of apparent social types.

Keywords:

• oocyte development
• oocyte resorption
• Cerceris
• nest sharing