Context-dependent misclassification of masquerading prey

Masquerading prey resemble inedible objects such as leaves, twigs, stones and bird-droppings; and benefit because their predators misclassify them as the objects that they appear to resemble. From previous work on the importance of context cues in animal learning, we predict that predators will be less likely to misclassify masquerading prey as their models when they are found in a context in which predators have never before experienced the model. Here, we test this prediction using domestic chicks Gallus gallus domesticus as predators and twig-mimicking larvae of the Early Thorn moth Selenia dentaria as masquerading prey. We found that the benefit of masquerade was significantly larger when the twig-mimicking caterpillar was found in the context in which birds had previously experienced twigs. This suggests that masqueraders may have to pay opportunity costs associated with matching their models in position and microhabitat; and that predators' classification decisions are complex and multi-factorial.