This blog post is provided by José A. Carbonell, Ying-Jie Wang & Robby Stoks and tells the #StoryBehindThePaper for the article “Evolution of cold tolerance and thermal plasticity in life history, behaviour and physiology during a poleward range expansion“, which was recently published in Journal of Animal Ecology.
Many species are moving polewards due to climate change. During these expansions, species encounter novel thermal regimes to which they have to adapt. Therefore, rapid evolution of thermal tolerance and of thermal plasticity in fitness-related traits in edge populations is crucial for the success and speed of range expansions and population establishment in these newly occupied margin regions.
In a recent study that appeared in the Journal of Animal Ecology, we tested for adaptation in cold tolerance and in life history, behavioural and physiological traits and their thermal plasticity in the aquatic larval stage of the damselfly species Ischnura elegans during poleward range expansion (Vander Linden 1820). This species is a common damselfly species in Europe with its historical core range reaching from southern France to southern Sweden. It is currently showing a poleward range expansion in northern Europe. We reconstructed the thermal performance curves of life history (survival, growth and development rates), behaviour (food intake) and cold tolerance (chill coma recovery time) in the final larval stage of this damselfly when reared in the laboratory from eggs collected in the field. In this common-garden experiment, we studied larvae from three edge and three core populations in the Swedish expansion region.
Consistent with the colder annual temperatures, larvae at the expansion front evolved to improve their cold tolerance. In general, the larvae at edge populations showed no overall (i.e. across rearing temperatures) evolution of a faster life history that would improve their range-shifting ability. Yet, edge populations evolved at the highest rearing temperature (28 °C) had a faster development rate, likely to better exploit the rare periods with higher temperatures. This faster development at stressful temperature conditions was associated with a higher food intake and a lower metabolic rate.
Our results suggest that the edge populations rapidly evolved adaptive changes in trait means and thermal plasticity to the novel thermal conditions at the edge front. Our results highlight the importance of considering besides the evolution of trait means, also the evolution of trait plasticity to improve forecasts of responses to climate change.
Carbonell, J.A., Wang, Y.J. & Stoks, R. (2021). Evolution of cold tolerance and thermal plasticity in life history, behaviour and physiology during a poleward range expansion. Journal of Animal Ecology. DOI: 10.1111/1365-2656.13482