ZANI, P.A.*; BRADSHAW, W.E.; HOLZAPFEL, C.M.; LUCERO, K.D.: The Thermal Tolerance of the Pitcher-Plant Mosquito, Wyeomyia smithii

We examined the pitcher-plant mosquito, Wyeomyia smithii, from three northern and three southern populations to determine if a latitudinal gradient existed in their thermal tolerance. While many comparative studies among species have demonstrated a robust relationship between thermal tolerance and prevailing temperature at the locality of origin, we found within Wyeomyia smithii no differences in the critical thermal tolerance of mosquito populations spanning 30 to 46 degrees North latitude. This lack of difference in response to acute thermal stress is consistent with earlier studies that found no geographic difference in fitness in these same mosquito populations exposed to chronic lifetime thermal stress. Combined these results support the idea that the adaptive modification of the thermal response is a slowly evolving process among animals in nature.