S6-1.6 Sunday, Jan. 6 Using physiology to predict ectotherm responses to environmental change DIAMOND, SE*; PELINI, SL; ELLISON, AM; GOTELLI, NJ; SANDERS, NJ; DUNN, RR; North Carolina State Univ.; Bowling Green State Univ.; Harvard Forest; Univ. of Vermont; Univ. of Tennessee; North Carolina State Univ. firstname.lastname@example.org
Global changes in land-use and climate ensure that species are increasingly likely to encounter novel environments. This places a renewed urgency on understanding biological responses to environmental novelty. However, because these changes are occurring at a global scale with potential impacts on millions of species, we cannot develop predictions for how each species might respond. Rather, we need a predictive framework that reduces the dimensionality of this task by identifying key characteristics of those taxa and regions that are most at risk. We focus on the predictive ability of physiological tolerance of extreme temperatures in ectotherms. Here, we build upon our previous work showing that ants inhabiting lower latitudes tend to be at the greatest risk under climate change owing to environmental temperatures being close to their thermal limits. Among our two large-scale experimental warming arrays, positioned at the northern and southern boundaries of temperate hardwood forests in eastern North America, ant thermal tolerance was strongly predictive of ant responses at the low latitude site where temperatures routinely exceed ant thermal limits, but not the high latitude site where temperatures remain below ant thermal limits. While thermal tolerance explained a substantial portion of the variance in ant responses to warming, we found that carpenter ants (Camponotus sp.) were consistently some of the strongest outliers, occupying conditions well below their thermal limits. We further dissect the mechanisms underlying carpenter ant responses to warming, focusing on additional physiological traits including immune defenses and species interactions between ant hosts and their symbionts.