Grant: Discovery Grants Program - Individual

Increased warming and temperature variability are likely to impact how insects survive the winter through changes to cold stress, energy use, and pathogen infection. The consequences of changes in these challenges of the overwintering period are likely to linger into the growing season, thereby impacting immunity and the ability to transmit disease in insects such as mosquitoes. As winters change, we need to know if mosquito populations will suffer or explode, leading to changes in zoonotic disease risks and ecosystem functions. I will use comparisons among species and populations of mosquitoes to disentangle the drivers of overwintering mortality and subsequent fitness in the growing season. Mosquitoes are diverse (e.g. 31 species in Nova Scotia) and often have wide geographic ranges within a species (e.g. southern US to Canada) which allows us to use comparative studies to create generalizable or specific predictions of the outcomes of climate change. My first objective is to determine how winter climate change will impact physiology associated with winter survival and fitness: survival of low temperatures, infection with a mosquito-killing fungus, immunity, and energy use. I will compare these measures among six species of mosquitoes that are either native/established in Nova Scotia or predicted to expand their range northward into NS and the rest of Canada. We will simulate winter climate change in the lab to distinguish between the impacts of winter warming versus increased temperature variability. We will also compare these outcomes to mosquitoes that overwinter in the field to determine if our lab exposures capture the drivers of overwintering success among species. My second objective is to determine if we can expect population-specific responses to climate change in mosquitoes. We will collect the invasive Asian Tiger mosquito, Aedes albopictus, across a range of latitudes in Canada and the US to establish populations in our lab. We will determine if the populations differ in their genetics using microsatellite loci and assess their physiology associated with winter survival (e.g. immunity, infection and energy use, as in the first objective). Overall, we will provide data that can be used to model short- and long-term shifts in mosquito abundance and vector competence with climate change. Understanding these shifts allow us to predict and mitigate disease risk with zoonotic pathogens, as well as predict changes in insect biomass and biodiversity. We will also be able to identify temporal windows of susceptibility to biocontrol, which can help us to mitigate any increases in vector-borne disease risk with climate change in Canada.