The aim of this research is to gain an increased understanding about biochemical mechanisms insects use to survive the winter. While many insect species are known to overwinter in a state of diapause (dormancy) our understanding of the biochemical changes that occur during diapause and permit this long-term survival under adverse conditions is limited. Additional knowledge in this area could lead to new biorational approaches for the control of some pest insects. This proposal focuses on the regulation of the larval diapause of the southwestern corn borer, Diatraea grandiosella. Since lipids serve as a major reserve nutrient for survival during its diapause, the role of the lipids-transporting protein, lipophorin, is being examined in diapause larvae. Although lipids are known to be released from the fat body and transported in the hemolymph to sites of utilization during diapause, little is known about how the process of lipid release from the body fat occurs. The synthesis, processing, and release of lipophorin from the fat body of non-diapause and diapause larvae will be compared in a study and should substantially increase knowledge about the relationship between lipophorin and diapause and provide new information about how lipid reserves are sequestered and then mobilized to sustain insects during a prolonged period of dormancy. Ultracentrifugal, electrophoretic, immunochemical, radioisotopic, and electron microscopic techniques will be employed to do the proposed experiments.
