Evolved differences in thermal plasticity of mosquitofish mating behavior are unrelated to source temperature

Phenotypic plasticity in response to temperature is expected to play a key role in how organisms cope with climate change. Evolved differences in plastic responses are often linked to historical differences in average temperatures, yet we know little about how behavioral plasticity is affected by prevailing thermal environments. In this study, we used a common-garden design to test whether historical differences in average temperatures caused evolutionary divergence in the plasticity of mating behavior of Western mosquitofish (Gambusia affinis) inhabiting geothermal springs with average source temperatures spanning from 18.8 to 33.3 C. We found population differences in the thermal plasticity of courtship displays, copulation attempts, copulations, and mating efficiency, but these differences could not be explained by average source temperatures. We also tested for differences in thermal optima and maximum performance in mating behavior among populations. We found that only the maximum ...