When fear kicks in: predator cues initially do not but eventually do affect insect distribution patterns in a new artificial pond cluster

Abstract

Evidence has accumulated that colonization of new habitats by aquatic insects is often selective rather than random. However, it is still unclear how habitat selection changes during a colonization sequence. We studied colonization of adult aquatic beetle and bug communities in cattle tanks exposed to fish predation or predation risk repeatedly over time. This allowed us to quantify the relative importance of habitat selection and consumption by a predator on communities. Habitat selection explained about 25 and 43% of the total predator effect on the final species richness and abundance, respectively. While other studies on fish cues affecting beetle colonization typically found effects on species richness in the first 3 weeks, we only saw a response after 6 weeks. The observed slower and weaker effects of predation risk on habitat selection by adults in the current study, conducted after the reproduction phase of aquatic beetles and bugs, might be due to seasonal variation in the response to predation risk. The relative importance of predation risk as a driver for habitat selection might be lower outside the reproduction period when the most vulnerable life stages are absent.