Integrative biology of insects at low temperatures

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Most temperate insects spend more than half their lives overwintering. Overwintering success can be very important for insect populations and therefore ecosystem function. The proposed research will explore insect overwintering at multiple levels, from molecular mechanisms to large-scale geographic patterns, with the intention of improving our ability to predict the effects of climate (and climate change) on insect populations. Five main directions are proposed. 1) Recent work in my lab suggests that crickets die at moderately low temperatures because they are unable to control water and ion balance in their gut. I propose to study this in a range of species to determine whether it is a general explanation for insect chilling injury, and to identify the mechanisms that fail and lead to the imbalances. 2) I will investigate whether failure of the sodium- potassium-ATPase ion pump is the reason that insects stop being able to move (enter chill coma) at low temperatures. 3) Recent work suggests that cold-exposed insects upregulate their immune systems. I will investigate the interplay between immune responses and cold tolerance, with a view to understanding how this happens, and to identify the reasons for the increased immune response. 4) The eastern spruce budworm is a devastating boreal forest pest. I will use studies of gene expression to determine the condition of overwintering larvae. In the long term, this will lead to diagnostic tools that will allow the physiological state of the overwintering population - and therefore their subsequent performance - to be assessed as part of the management strategies for this species. 5) The willow leaf beetle, Chrysomela aeneicollis, is a widespread montane herbivorous insect in the Western mountains. Warmer winters can be good for this species, because they reduce the incidence of potentially lethal cold exposure, but changes in snow cover will modify the timing of cold exposure as well as the amount of energy used. energy use and . I will use a combination of field and laboratory studies to explore the interplay between aspects of changing alpine climate to develop a predictive model of climate change effects on this species. This work will significantly advance our understanding of insect biology at low temperatures, and will also help to predict the responses of insects to changing climates, which will be widely applicable in agriculture, forestry, invasive species management and conservation.