The long term goal of the project is to understand how the endocrine system organizes complex programs of behavior. The project focuses on the ecdysis behavior of insects, a stereotyped behavioral sequence that enables the insect to shed its old skin at the end of a molt. The ecdysis sequence is divided into 3 main phases, each of which is dependent on the release of a different hormone: ecdysis-triggering hormone, crustacean cardioactive peptide, and bursicon, respectively. Molecular genetic approaches will be used in Drosophila to determine the molecular and cellular organization of this hormonal control system and how sensory stimuli can alter hormone release thereby providing behavioral plasticity. The project will focus on ecdysis behavior, which is influenced via two pathways, one through declining steroid titers, which encode developmental information, and the other through neurohormones that provide a pathway for proximal behavioral stimuli. Photoperiod shifts and steroid manipulations and measurements will be used to define how steroids interact with the behavioral program, and mutants used to identify novel components of this pathway. The project will then use genetic manipulation of particular neurons to examine the premature activation of the last behavioral phase, before ecdysis is completed. These flies will allow the determination of the regulatory circuitry that couples two behavioral modules together. The timing of bursicon release will be examined under various conditions and bursicon mutants used to determine if bursicon is responsible for terminating ecdysis. Insect ecdysis has become a premiere system for studying how hormones regulate complex behavior. However, these relatively simple behavioral assays will be an excellent avenue to train undergraduates in bench science working on this project. Undergraduates and pre-college students, some of which are women and under-represented minorities, will be involved in this project that offers exceptional research training oppportunities.
