Aedes atropalpus (Diptera: Culicidae) growth rates are depressed at low temperatures where Aedes japonicus japonicus is more abundant in rock pools

The North American rock pool mosquito, Aedes atropalpus (Diptera: Culicidae), is a non-biting species that uses riverine rock pools for immature development. In the United States, this native species coinhabits rock pools with an invasive vector, Ae. j. japonicus. Reports of reductions in the abundance of Ae. atropalpus have led researchers to hypothesize that Ae. j. japonicus is displacing the native species. Aedes atropalpus remains well-established in warm, unshaded rock pools where Ae. j. japonicus is rare, while Ae. j. japonicus is a temperate species that is more commonly encountered in colder pools. Because there is a paucity of historical data, it is unclear whether Ae. atropalpus was highly abundant in temperate rock pool habitats in southern Appalachia prior to the introduction of Ae. j. japonicus. To determine whether Ae. atropalpus can successfully develop in temperate pools, we reared Ae. atropalpus larvae at three ecologically informed temperature ranges (16-20°C, 23-27°C, 30-34°C). We used common fitness correlates (size, survival, fecundity, and development time) to estimate the species’ finite population growth rate at each temperature. Our results demonstrate that the growth rate of Ae. atropalpus is depressed at cold temperatures where Ae. j. japonicus is dominate, but also that the optimal developmental temperature of Ae. atropalpus species may be near that of Ae. j. japonicus. Aedes atropalpus may avoid ovipositioning in cold, shaded pools, but there is a mid-range temperature (23-27°C) where competitive interactions are likely to occur with Ae. j. japonicus.