P2.7 Thursday, Jan. 5 Stress Response Correlates with Reduced Calling Capacity in Spring Peepers (Pseudacris crucifer) MANGIAMELE, LA*; BEVIER, CR; CAROL, HA; KING, KR; Bowdoin College, Brunswick, ME; Colby College, Waterville, ME; Bowdoin College, Brunswick, ME; Colby College, Waterville, ME email@example.com
Frogs provide an excellent model to study the physiological constraints on communication behavior. Male Pseudacris crucifer use advertisement calls to attract females to mate, and females prefer males with higher call rates. However, the production of acoustic signals is energetically costly, thus variation in the ability to mobilize energy stores, such as lipid and glycogen, likely contributes to variation in call rate and perhaps ultimately male mating success. Recent work suggests that variation in male frog vocalizations is correlated with individual responses to environmental stressors, but the potential physiological effects of stress hormones, such as corticosterone (CORT), on the muscles involved in vocalization has not been studied. To address this question, we observed male P. crucifer during the breeding season (April – June) and recorded their calls. We then sacrificed them and collected trunk muscles and blood samples. We measured levels of stored lipid and glycogen in muscles as indicators of energy available for call production, and activity levels of citrate synthase as an indicator of muscle aerobic capacity. We measured plasma levels of CORT to evaluate responses of males to environmental stress. We found that CORT was negatively correlated with citrate synthase; males with high levels of corticosterone had significantly lower levels of citrate synthase activity. In addition, males with high levels of corticosterone tended to have lower call rates. Percent lipid content and glycogen content of trunk muscles were not correlated with either CORT levels or calling rate. These data suggest that male P. crucifer that are more affected by environmental stressors have less energy available for calling and produce a less attractive advertisement calls.