Warming drives higher rates of prey consumption and increases rates of intraguild predation

This is an Accepted Manuscript of an article published by Springer in Oecologia in April 2018, available online: https://doi.org/10.1007/s00442-018-4146-y. The supplementary materials are available at https://doi.org/10.1007/s00442-018-4146-y#Sec25Warming due to climate change is expected to alter species interactions. These interactions are shaped by components of individual behavior, particularly foraging behaviors. However, few studies consider species’ behavioral responses to warming to predict how species interactions will be affected by warming. We chose two complementary approaches to examine how climate warming may affect the behavior and interactions of aquatic intraguild predators. First, we measured behavioral responses to warming in six larval dragonfly species, expecting that feeding rate and activity would increase with temperature. Secondly, we conducted intraguild predation (IGP) trials with three species to understand how temperature affects IGP, and if species’ behavioral responses to warming are indicative of the outcome of IGP interactions. Warming increased feeding rates by 42% on average across species but had no effect on activity rate. The magnitude of change in feeding rate was positively correlated with the maximum temperatures species experience across their ranges. Lastly, warming increased rates of IGP twofold, however, species’ behavioral responses alone were not predictive of their susceptibility to become IG prey of other larvae at warmer temperatures. Our results provide evidence that IGP interactions may be greatly affected by future increases in temperature; however, activity responses to warming alone are weak predictors of the outcomes of these interactions. Future studies should consider other species’ traits when forecasting the effects of climate change on species interactions.Zimmerman/Weis Graduate Award, the Koffler Scientific Reserve, and funding from the Department of Ecology & Evolutionary Biology, the University of Toronto, and from the Department of Biology, the University of Toronto Mississauga, awarded to DNF. Natural Sciences and Engineering Research Council of Canada Discovery Grant (# 435614), Canada Foundation for Innovation John R. Evans Leaders Fund, and Ontario Leaders Opportunity Fund awarded to SJM