John Ewer, Associate Professor

Research Interests

I am interested in the neural and genetic control of behavior. The main project in the lab is understanding the mechanisms that controls ecdysis, the behavior that allows insects to shed their old cuticle. Insect growth occurs through multiple stages. At the end of each stage the animal molts and produces a new cuticle for the next stage. The molt culminates with ecdysis, the shedding of the old cuticle.

The occurrence of ecdysis is tightly regulated, both by development, as well as by the biological clock (at adult emergence). Both its timing as well as its execution is controlled by a number of interacting neuropeptide hormones. Thus, ecdysis behavior is a good model system for understanding how behavior is coordinated with development, how neuropeptides and neurohormones regulate behavior, and how the circadian (biological) clock causes behaviors to be express a circadian rhythmicity.

Most of our work is carried out using Drosophila, taking advantage of the genetic and molecular tools available in this organism to identify components involved in the control of ecdysis behavior, and determine their role in vivo. We also use other insect species to examine how the control of this behavior has changed during insect evolution.

Expression of CCAP RNA (right) in CCAP immunoreactive neurons (left) in the Drosophila CNS. Work on the moth, Manduca sexta, strongly suggests that the peptide Crustacean Cardioactive Peptide (CCAP) is central to the control of ecdysis. We have initiated the genetic analysis of CCAP function in Drosophila by examining the behavior of transgenic flies bearing targeted ablations of CCAP neurons (Park et al., 2002). Arrows and arrowheads point to neurons expressing CCAP. Br: brain; vns: ventral nervous system.