Social regulation of reproduction is the foundation of colony organization in social insects. Yet so little is known about the basic process of oogenesis itself, it is difficult to do more than guess what physiological processes are blocked to result in sterility. The long-term objective of the proposed research is to define the endocrine basis of oogenesis in social insects and to identify the mechanisms by which reproductive females sterilize in nestmates. Workers of the ant genus Camponotus present many features that make an in-depth study of oogenesis and its inhibition feasible. In the first year of the project, the investigator will define oogenesis and its inhibition in workers phenomenologically and morphologically. She will produce antibody to vitellogenin (Vg.) and use it in the study of Vg synthesis in vivo. Honeybee Vg and Vg antibody will be used to develop protocols that can be applied to ants. Next, in vivo endocrine studies (e.g., assay of ecdysteroid titers, effects of exogenous juvenile hormone on oogenesis) will begin. A defined culture medium for in vitro studies and an antibody-based assay for quantification of Vg will be developed. Then, the investigator will begin in vitro studies on Vg synthesis by fat body. During the third year of the proposed research, the responsiveness of fat bodies in different physiological states to hormonal challenges will be determined. The investigator will test the feasibility of studying the role of the ovary, including ecdysteroid secretion and Vg uptake, in vitro.
