David Polcyn

Physiological ecology of animals, especially those inhabiting extreme environments.
Current research focuses on the physiological and behavioral adaptations of insects to desert environments. Large flying insects such as dragonflies are a conspicuous component of the desert fauna, and are active throughout the extremely hot Mojave desert summers. Work conducted on an assemblage of species inhabiting ponds at the University's Soda Springs Desert Studies Center has shown elevated body temperature regulation and tolerances in the desert populations relative to related species inhabiting cooler environments. I have also studied metabolic rates of desert dragonflies and found them to be quite high compared to most other flying insects. Behavioral studies are currently being conducted in order to determine time-energy budgets of these desert populations. This information on temperature regulation, metabolic rates and activity patterns will provide insight into the energetic and ecological cost of adaptation to an extreme thermal environment. A new phase of research includes the electrophoretic analysis of these same desert dragonflies to: 1) determine and compare the population structure of numerous species in several isolated desert habitats; 2) identify the specific adaptations in flight muscle enzyme systems underlying the thermal tolerances unique to the populations inhabiting the desert; and 3) identify the role heat shock proteins play in the increased thermal tolerances in desert populations. Thus, my research on the ecology of a single community of dragonflies spans the breadth of the biological disciplines, from the molecular through to the community levels, with emphasis on a thorough understanding of adaptation at the level of the individual.