Associate Professor Stanford University, United States
Abstract: Climate change has the potential to affect interactions between parasites and their hosts. A warming environment may alter patterns of local adaptation, favoring either the parasite or host and thus increasing or decreasing the prevalence of disease. In this study we aimed to assess temperature-mediated patterns of local adaptation in the western tree hole mosquito Aedes sierrensis and its facultative ciliate parasite Lambornella clarki. We reared mosquito larvae and parasites collected from across a climate gradient under common lab conditions with varying temperatures, implementing a host population by parasite population by environment (GH x GP x E) experimental design. Our findings reveal that Lambornella are locally adapted to their mosquito hosts, with higher infection rates observed on sympatric populations compared to allopatric populations. However, Lambornella do not appear to be locally adapted to temperature in their parasitic form, despite showing a signal of adaptation to temperature in their free-living form. Additionally, we found that infection rate was highest at the intermediate temperature. Together, our results suggest that selection imposed by the host may be stronger than that imposed by the thermal environment and that the response of this host-parasite system to climate change is likely to be complex.
