Predatory events are common in natural circumstances, though those actual actors are usually difficult to observe in the field. Beak mark on the butterfly’s wing, possibly showing the evidence of the avoidance from a predator following its attack, might evaluate the intensity of predator-prey relations in the field as well as the survival rate of butterflies. Here, I compared the abundances of butterflies with beak mark and their predators in relation to the habitat characteristics.

Field surveys were conducted in 4 sites in Shiga Prefecture, Japan, with different landscapes during May ~ Nov 2010, using the route census observation for butterflies and their predators.

The ratio of butterflies with beak mark increased with increasing predator density. Interestingly, the composition of butterflies with beak marks was different among these areas.

Plausible explanation is that, even for butterflies in the edge where most of butterflies are inhabiting, predation pressure and/or escape ability are different related to the quality of neighboring open environment (grassland). Also the quality of shaded environment (inside of woodland) is probable to affect the opportunity of butterfly’s escape from predator. Therefore, the beak mark on the wing of butterflies might be an useful indicator to evaluate the prey-predator relationship as well as the quality of habitats.