Meeting Abstract

93.2  Tuesday, Jan. 6 13:45  Oxidative stress during disruption of gas exchange patterns in insects HEINRICH, EH*; BRADLEY, TJ; University of California, Irvine; University of California, Irvine eheinric@uci.edu

Insects utilize an efficient gas exchange system made up of tracheal tubes which deliver oxygen directly to tissues. Since oxygen delivery bypasses the circulatory system and depends only on diffusion through air and some fluid filled tracheoles, it is possible for insects to have high tissue P_O2 values. However, insects can maintain a low internal P_O2 through the use of prolonged spiracle closures and micro-openings, also referred to as discontinuous gas exchange cycles. The oxidative damage hypothesis proposes that discontinuous gas exchange provides an adaptive advantage to insects by preventing excess oxidative damage during periods of low metabolic demand. We tested this hypothesis by disrupting the respiratory pattern of Manduca sexta pupae and Drosophila melanogaster adults by exposure to mild hypercapnia. Superoxide dismutase activity and oxidative damage of lipids and proteins were quantified in insects with disrupted respiratory patterns and compared to damage in insects with normal respiratory patterns. This study provides a direct tests of the oxidative damage hypothesis and may suggest a mechanism by which insects protect themselves from oxidative damage while maintaining a high metabolic scope.