9Predator nonconsumptive effects (NCEs) on prey activity are common in nature. Upon sensing 10 predator cues, a common prey response is to reduce feeding to avoid being detected by predators. 11Using an aquatic system, this study investigated how prey density and predator cue type affect 12 predator NCEs on prey feeding. Prey density was investigated because, as it increases, the 13 individual risk of being preyed upon decreases, which may reduce NCEs if prey can detect 14 conspecifics. Predator cue type was investigated because waterborne cues would trigger weaker 15NCEs than waterborne and tactile cues combined, as predation risk may be perceived by prey to 16 be stronger in the second case. Specifically, a factorial experiment tested the hypotheses that (i) 17 increasing dogwhelk (prey) density reduces the limitation that crab (predator) chemical cues can 18 have on dogwhelk consumption of mussels and that (ii) chemical and tactile crab cues combined 19 limit dogwhelk feeding more strongly than chemical crab cues alone. The results broadly 20 supported these hypotheses. On the one hand, crab chemical cues limited the per-capita 21 consumption of mussels by dogwhelks at a low dogwhelk density, but such NCEs disappeared at 22 intermediate and high dogwhelk densities. On the other hand, the combination of chemical and 23 tactile cues from crabs caused stronger NCEs, as dogwhelk consumption of mussels was 24 negatively affected at all three dogwhelk densities. The structurally complex mussel beds may 25 provide not only food for dogwhelks but a refuge from crab predation that allows dogwhelk 26 density to limit crab NCEs when mediated by waterborne cues. Overall, this study suggests that 27 prey evaluate conspecific density when assessing predation risk and that the type of cues prey are 28 exposed to can affect their interpretation of risk. 29
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.