Behavioural response to simulated avian predation varies with latitude and predation intensity of natural populations

Abstract

The intensity of ecological interactions is generally expected to increase at lower latitudes, suggesting potential to shape prey behavior at broad spatial scales. Yet, there is relatively limited understanding of how animal behavior varies across major environmental gradients for most taxonomic groups. In this study, I investigated behavioral response of a livebearing fish, Gambusia holbrooki, to a simulated avian predator. Fish originated from 17 populations distributed across 15° latitude. Across this latitudinal expanse, the richness of piscivorous birds varied significantly. Consistent with putative predation pressure, antipredator responses were more frequent in regions with greater inferred predation pressure. Predator richness and latitude covaried significantly across the study region, indicating a need to further disentangle drivers of behavioral evolution including potentially correlated unmeasured variables. Nonetheless, this study demonstrates the importance of environmental variation for shaping patterns of animal behavior at a broad spatial scale (2000+ km), which may be important for understanding a range of ecological processes such as disease transmission and invasion dynamics.