Ecology of Fear in Rusty Crayfish: Preference Between Distance and Shelter Quality Under Threat of Predation by Largemouth Bass in Northern Michigan

Climate change is expected to shift weather patterns and precipitation rates, leading to more frequent and intense extreme weather events such as droughts and storms. These deviations could wipe out and reset aquatic habitats, depleting food, water, and shelter resources. Under the landscape of fear theory, an organism's use of resources within an environment is shaped by the presence of predators and the sensory landscape they create. The predator-induced stress experienced by prey species is understood to impact the broader population and ecosystem under the ecology of fear framework. Climate change-induced decreases in shelter availability could dramatically alter the population dynamics within the ecohydrological system. This study examined rusty crayfish shelter resource use (Faxonius rusticus) for different quality shelters as a function of distance from the predator signals of largemouth bass (Micropterus salmoides). Two size-matched female crayfish were placed in flowing mesocosms downstream of bass to expose them to predator cues. We assessed antagonistic interactions and shelter use through video assays. Linear mixed models revealed that rusty crayfish showed preference only for high-quality shelters close to the predator cue source compared to controls and other spatial configurations. This suggests that crayfish gauge their distance from a predator and will only seek shelter at a level of critical proximity. Secondly, the shelter must be of a certain quality or else it is of no advantage over further distance from the threat.