Ecological adaptations by ant colonies in response to thermal stress due to climate change

Animals can change behavior to respond immediately to the environmental stress caused by climate change. Animals that live in cooperative groups can mount additional coordinated social responses to ameliorate the stress of increasing temperature. Elevation gradients offer an opportunity to test how organisms will react to climate change. Studies across plants and animals show that species are moving upward as temperatures increase. However, this is constrained due to competitors already occupying those niches.
My work focuses on two species of seed-dispersing Aphaenogaster ants found in the forests of eastern United States. A. rudis is warm-tolerant, low-elevation species whereas A. picea is a cold-tolerant, high-elevation species. I am studying the performance of colonies in the field across an elevation gradient in Shenandoah National Park. I also collected colonies of both the species from their upper and lower elevational limit and kept them at two different temperature treatments in the lab to study the combined effect of elevation and temperature. To test the climate-mediated effects of competition between the two species for resources, I will measure foraging efficiencies at temperatures representative of summer extremes at either side of the elevational transition zone. I predict that A. rudis will perform better (measured as food resources acquired, and offspring raised) at the high temperature, while A. picea will show the opposite pattern. I am also studying the physiological adaptations of the two species to thermal stress. Understanding the ecological adaptations of ants is crucial to predict changes in the ecological services they provide.