Trait-mediated functional responses: predator behavioral type mediates prey consumption

1. The predator functional response (i.e. per capita consumption rate as a function of prey density) is central to our understanding of predator-prey population dynamics. This response is behavioral, depending on the rate of attack and time it takes to handle prey. 2. Consistent behavioral differences between conspecific individuals, termed behavioral types, are a widespread feature of predator and prey populations but the effects of behavioral types on the functional response remain unexplored. 3. We tested the effects of crab (Panopeus herbstii) behavioral type, specifically individual activity level, on the crab functional response to mussel (Brachidontes exustus) prey. We further tested whether the effects of activity level on the response are mediated by the presence of toadfish (Opsanus tau) predation threat in the form of waterborne chemical cues known to reduce crab activity level. 4. The effects of crab activity level on the functional response were dependent on crab body size....