Data from: Evidence for the Predator Attraction Hypothesis in an amphibian predator-prey system

Many species possess damage-released chemical alarm cues that function in
alerting nearby individuals to a predator attack. One hypothesis for the
evolution and/or maintenance of such cues is the Predator Attraction
Hypothesis, where predators, rather than prey, are the ‘intended’
recipients of these cues. If a predator attack attracts additional
predators, these secondary predators might interfere with the predation
event, providing the prey with a better chance to escape. In this study,
we conducted two experiments to explore this hypothesis in an amphibian
predator/prey system. In Experiment 1, we found that tiger salamanders
(Ambystoma mavortium) showed a foraging attraction to chemical cues from
wood frog (Lithobates sylvaticus) tadpoles. Salamanders that were
experienced with tadpole prey, in particular, were strongly attracted to
tadpole alarm cues. In Experiment 2, we observed experimental encounters
between a tadpole and either one or two salamanders. The presence of the
second predator caused salamanders to increase attack speed at the cost of
decreased attack accuracy (i.e., increasing the probability that the
tadpole would escape attacks). We also found that the mere presence of
visual and chemical cues from a second predator did not affect this
speed/accuracy trade-off but did cause enough of a distraction to increase
tadpole survival. Thus, our findings are thus consistent with the Predator
Attraction Hypothesis for the evolution and/or maintenance of alarm cues.