Attack cone avoidance during predator inspection visits by wild finescale dace (Phoxinus neogaeus): the effects of predator diet.

When confronted by potential predators, many prey fishes engage in predator inspection behavior. Previous authors have argued that by selectively avoiding the predator's head during an inspection visit (attack cone avoidance), individual inspectors may reduce their local risk of predation. In field trials, we investigated the effects of predator diet cues on the presence of 'attack cone avoidance' during predator inspection visits. Wild, free-ranging finescale dace (Phoxinus neogaeus) were exposed to the combined cues of a model predator and a distilled water control or the odor of a yellow perch (Perca flavescens) fed dace (with alarm pheromone), swordtail (Xiphophorus helleri) (lacking Ostariophysan alarm pheromone), or perch that were food deprived for four days. Finescale dace modified their predator inspection behavior following exposure to the odor of a perch fed dace (fewer dace present, reduced frequency of inspections, and an increased per capita inspection rate) compared to those exposed to the odor of a perch fed swordtails, perch that were food deprived, or a distilled water control. In addition, dace inspected the tail region more often only when the model predator was paired with the odor of a perch fed dace. In all other treatments, dace inspected the head region of the model predator more often. These data suggest that attack cone avoidance of inspecting prey fishes may be more likely to occur in high-risk situations, such as in the presence of conspecific alarm pheromones in the diet of potential predators.