Along with Lauren Nadler and Clive Trueman of the University of Southhampton, we’re searching for a PhD student to examine how group living may offset the effects of stress in fish. Apply here! (deadline January 3, 2023).
Group living is common across the animal kingdom, ranging from the tiniest insects to the largest mammals. The ubiquity of sociality suggests that it imparts several benefits to individual group members. However, the evolutionary drivers of social behaviour within and among animal species remain obscure. One advantage of group living may come in the form of energy savings. Group-living individuals may reduce energy needs by sharing the costs associated with daily activities, such as movement and finding food. Social individuals may also benefit from the “calming effect”, in which energy use drops as the group can take advantage of having “many eyes” to scan for predators and reduce everyone’s investment in predator avoidance. Recent work in a social fish species found that socializing can reduce metabolic rate by 25% on average when compared to social isolation, with this calming effect persisting even under projected future ocean acidification. This project will take a comparative approach to social fishes to identify what characteristics predispose a fish species to be “calmer” in a social context and determine whether environmental traits alter the magnitude of this energetic benefit.
Methodology
Using social fishes as models, this project will combine techniques in animal behaviour, ecophysiology, and otolith geochemistry to explore the energetic consequences of sociality, with results applicable to social species from a range of taxa and habitat types. This PhD project will take advantage of recent technological advances for measuring the metabolic rate of social fishes in the laboratory and field to test: 1) the prevalence of the calming effect among social fishes, 2) the role of environment and social context in modifying the strength of this effect, and 3) the mechanistic drivers underpinning calming effects. These research questions will be addressed using techniques such as animal personality tests, intermittent-flow respirometry, and assays of otolith geochemistry. Comparisons will be drawn among temperate and tropical fishes, with potential for fieldwork in a range of settings depending on the interests of the candidate.