Generally, ectotherms rely on natural environmental temperature variation to regulate body temperature. Many physiological processes in ectotherms can be sensitive to body temperature, including locomotion, and these processes may play an important role in foraging and mating behavior. Here, we investigated how walking performance varies across a range of naturally occurring habitat temperatures in Enchenopa binotata treehoppers (Hemiptera: Membracidae). Enchenopa binotata are small, ectothermic insects that locate mates through the exchange of long-range vibrational duets while males move along the plant stems. First, we acclimated individual males and females to testing temperatures that were ecologically relevant (18 - 36 °C). We then measured the duration of time to walk 10cm on a vertical wooden dowel at each testing temperature. To induce walking, we placed a paintbrush .5 cm behind the abdomen of each individual as they moved up the wooden dowel. We found that walking performance was faster at hotter temperatures and that males and females did not differ in walking speed across temperatures. Individual variation in walking speed was high across all temperatures. However, individuals did not vary in the thermal sensitivity of their walking speed, which may point to strong selection on the thermal sensitivity of walking performance. Overall, our results suggest that behavioral processes which include a walking component, such as mate localization, may be sensitive to temperature. This sensitivity may have important fitness consequences for ectotherms in variable thermal environments.

Emily Miller would like to thank their faculty sponsor Dr. Fowler-Finn for their support of this project.