UC Riverside

Endocrine state is an emergent phenomenon; hormonal coregulation in multicellular organisms generally establishes a malleable endocrine “backbone” which allows individuals to coordinate a systemic response to environmental and physiological stimuli. While endocrine networks regulating reproduction in vertebrate systems are very well-defined, the post developmental networks in arthropoda lack clarity. Using the model insect Drosophila melanogaster, with its exceptional genetic tractability, this dissertation elucidates a novel hormone network regulating reproduction and courtship, and demonstrates how this network affords the organism versatile control of reproductive behaviors. Developmental hormones 20-hydroxyecdysone (20E) and juvenile hormone (JH) have well-defined roles as gonadotropins among insects, but ecdysis triggering-hormone (ETH) has been largely ignored, despite its prevalence and critical role in development. This work here provides evidence that ETH provides a link between these two hormones, and relays hierarchical information regarding endocrine state to a variety of targets which regulate male and female reproduction. Taken together, data from this dissertation support the hypothesis that Drosophila reproduction is tightly regulated by 20E, ETH and JH, which work in tandem to ensure coordination of physiology and environment.