Effects of changing temperatures on social behavior via effects to metabolism in the common minnow (Phoxinus phoxinus)

Abstract

Social behavior is an important part of the life of many animals with consequences for foraging and predator avoidance. In many species, individuals consistently vary in how social they are, which has consequences for group level dynamics. Recent work has found that individuals with a higher metabolic rate are less social, likely because they prioritize finding food over avoiding predators. In ectothermic animals like fish, temperature influences metabolic activity with higher temperatures leading to an increase in metabolic rate. As an individual fish moves through its environment, it is exposed to temporally and spatially different temperatures which could alter the individual motivation to engage in social behavior. Warming temperatures caused by climate change could also lead to reductions in social behavior and changes in overall group cohesion via effects on metabolic rate. However, the speed by which changes in metabolic rate affect expressed social behavior is not well understood. To test this, we acclimated common minnows (Phoxinus phoxinus) to three different temperatures (14, 17 and 20˚C) over 4 weeks. We then measured maximum metabolic rate, standard metabolic rate and aerobic scope at acclimation temperature. In addition, we measured the routine metabolic rate, individual social behavior and group cohesiveness over a gradient of ramping temperatures (up to 23˚C). The results of this study will shed light into the effects of environmental change not only on an individual’s physiology and behavior but also on group behavior, which is essential to better predict the capacity of species to cope with climate change.