Ongoing human induced climate change is increasing the frequency and duration of heatwaves, a pattern that is predicted to continue. These events represent important stresses for organisms that are shifted away from their physiological optima. Ectotherms living in temperate areas may be particularly susceptible to the effects of heatwaves, and heatwaves may interact with other threats from the environment, such as disease, to compromise population health. The thermal stress hypothesis suggests that thermal environments where maintenance of biological functions is energetically costly will reduce performance, and this will influence the ability of organisms to respond to the surrounding biotic environment. We tested the thermal stress hypothesis in relation to longevity, immunity, and resistance to parasite infection in age-controlled adult bumble bees exposed to a simulated, ecologically relevant heatwave versus bees experiencing a standard control thermal regime.
Results/Conclusions
Analyses of immunity (phenoloxidase and antibacterial assays) and infection outcome (based on Crithidia bombi infection prevalence and intensity measured via qPCR) are ongoing. However, survival data showed that heatwave treatment had a significant effect on subsequent survival, with decreased survival in heatwave-exposed individuals. This suggests that heatwaves can have important health related consequences for adult bumble bees. This work demonstrates how bumble bee health, and broadly pollinator health, can be impacted by the effects of climate change and will help guide predictions about the fate of our pollinators facing current threats to population stability.