9306650 Yin Phormia regina, the common black blowfly, has been used extensively to study various aspects of biology from feeding behavior to egg development. It is common knowledge that many adult insects need a protein meal before they can develop eggs. What remains to be understood, however, is how this happens or, more aptly put, "What is the link between nutrition and egg development." Previous research by the group has shown that there is a midgut hormone that provides this link. The current study is designed to purify and identify this hormone. Once this has been done, a test will be developed permitting the determination of the levels of this hormone in the insect's blood following a protein meal. Finally, the PI will use another test to determine where this hormone is produced and its site of action. The major significance of this research is that this new hormone may provide a new and novel way to interfere with and prevent egg development. Such a technique should serve as an exemplar model for controlling egg development in other insects. ***