Professor, Department of Biology Concordia University, Quebec, Canada
In order to maximize fitness, prey must assess predation risk using publicly available information. However, when publicly available information is unknown, prey face uncertainty of predation risk, or the inability to predict risk due to incomplete information. This uncertainty has been argued to increase neophobic responses among prey as an alternative to learning. Recent studies demonstrate that ambient predation levels, the reliability of information, and spatial and temporal predictability of novel (unreliable) cues shape neophobic responses. However, it is likely uncertainty is also shaped by how the environment alters the availability of information to prey. Variable environmental factors such as substrate complexity, substrate diversity, and stream velocity should decrease predictability of risk and increase uncertainty of risk. These environmental factors, and the variability in these factors, should therefore influence neophobic responses. In order to test how environmental variables might shape neophobic responses in Trinidadian guppies (Poecilia reticulata), we conducted an in situ field experiment of two guppy populations (high and intermediate ambient predation) designed to determine how the mean and variance of several environmental factors might influence the neophobic response to novel predator models and novel foraging patches.
We found that guppies from pools with high habitat complexity took longer to inspect predator models, but entered novel foraging arenas more quickly, than guppies from pools with low habitat complexity. Our results suggest differences in trade-offs for engaging in foraging and engaging in predator inspection behaviours. As substrate diversity increased, neophobic latencies increased as well, indicating that greater variability in substrate composition affected information availability and predictability of risk. Conversely, water velocity was a poor predictor of neophobic responses, perhaps due to the visual nature of our neophobic experiments. Our study provides evidence for how environmental variables shape neophobic responses via their effect on uncertainty of risk. It is important to examine how uncertainty of risk might shape neophobia, as we expect an increase in uncertainty due to climate change, habitat degradation, invasive species, and other anthropogenic factors.