The effect of single and multiple predator cues on survival, foraging and antipredator responses of the wolf spider, Pardosa milvina

Animals should allocate defensive responses proportional to the perceived threat. The wolf spider Pardosa milvina shows effective antipredator behavior in the presence of chemical cues from the co-occurring predatory wolf spider, Tigrosa helluo, which represents a chronic daily predation threat. The fishing spider Dolomedes tenebrosus is allotopic to Pardosa but, because of microhabitat preferences, is less likely to encounter Pardosa. We used differences in these species space use and encounter frequencies with Pardosa to independently manipulate perceived predation risk and measure Pardosa response to cues produced by these predators. We measured variation in Pardosa antipredator response to chemical cues produced from either Dolomedes, Tigrosa, or both species simultaneously and manipulated the location of these cues on vertical or horizontal surfaces. We quantified the foraging costs and survival benefits of such behaviors. Overall Pardosa discriminated between cues from Tigrosa and Dolomedes and showed adaptive graded responses proportional to the perceived threat