Food for thought: food availability alters crayfish perception of fear and safety in risky habitats.

Recent evidence shows that prey behavior is mediated by information regarding predators, refuges, and possibly food. However, the ways in which these 3 factors influence prey behavior in tandem with one another is still largely unexplored. We exposed rusty crayfish (Faxonius rusticus) to largemouth bass (Micropterus nigricans) odors and quantified sheltering and foraging behaviors. We presented crayfish with shelters of varying quality in 2 spatial arrangements and changed the location of a food source, Chara spp., to be near each shelter in different treatments. In this way, we created both a gradient of fear and of safety independently from one another while attempting to alter the perception of these gradients with changes to food location. We found that predator odor, refuge spatial arrangement, and food location were all important for crayfish behaviors. First, we found that time sheltering and time near shelters were both significantly impacted by interactions of shelter quality and arrangement. Crayfish only spent more time in and near upstream high-quality shelters when Chara spp. was also upstream. Next, we found that the average gape ratio of bass used in trials significantly altered the total amount of Chara spp. consumed, time spent foraging, and crayfish movement. The results of this study show the importance of information related to risk, safety, and food in altering prey behaviors, and these factors are used in combination. Specifically, the presence of a food source and the proximity of a food source to a shelter may affect where and when a prey organism shelters.