Meeting Abstract
Temperature significantly impacts organismal performance through its effects on muscle contractile rates, making the maintenance of performance across temperatures a critical environmental challenge for many animals. Thermal effects on performance can be mitigated in movements powered by elastic recoil, such as the ballistic tongue projection of salamanders. Here, we examine the effect of body temperature (5-25°C) on the feeding performance and muscle activity in plethodontid salamanders that exhibit muscle-powered or elastically powered tongue projection to examine how motor control maintains performance in these two kinds of systems. Kinematic analysis of feeding combined with electromyography of projector (SAR) and retractor (RCP) muscles reveals that elastically powered tongue projections are faster and less sensitive to temperature changes compared to their muscle-powered counterparts, but that, motor control is similarly affected by temperature in both kinds of systems. The SAR was activated earlier relative to tongue projection and for longer durations at lower temperatures, while RCP activity was less influenced by temperature. Muscle activation intensity in both the SAR and RCP did not vary at higher temperatures, but decreased at the lowest temperatures. These results demonstrate that muscle activity appears to be modulated to maximize performance in a similar manner at all temperatures in both muscle and elastically powered projections. However, motor control in elastically powered systems allows comparable energy to be stored in elastic tissues over a wide range of temperatures, reducing the temperature sensitivity of feeding performance.
