Sexual Dimorphism in Drosophila exercise motivation. Alyson Sujkowski, Sara Ginzberg, Robert Wessells. Univ Michigan, Ann Arbor, MI.

   Endurance exercise is a promising therapeutic intervention with substantial protective effects on multiple indices of healthspan, including muscle and neuronal function. Male Drosophila respond to a ramped daily program of exercise by inducing conserved physiological responses similar to those seen in mice and humans. Female flies, however, respond poorly to exercise induction and, as a result, do not induce the physiological changes seen in males, indicating a strong sexual dimorphism in response to exercise stimuli. Here, we demonstrate that poor female exercise response is behavioral, mediated by differences in neurons, not by differences in muscle. We also show that the sex specific motivation for exercise behavior is reversible even in adults, after development has been completed. Using tissue-autonomous sex determination constructs, we have sought to identify the minimum brain regions sufficient to govern adult exercise behavior. In addition, we find that sexually dimorphic exercise behavior varies between Drosophila species, suggesting that dimorphic exercise motivation may be specifically adaptive. Together, these findings indicate that, at least in flies, exercise motivation is a complex behavior controlled by the nervous system, and is independent of muscle. This model provides an important opportunity to further examine the specific changes in neural physiology that mediate behavioral motivation and plasticity.