A case of Batesian mimicry between a myrmecophilous staphylinid beetle, Pella comes, and its host ant, Lasius (Dendrolasius) spathepus: an experiment using the Japanese treefrog, Hyla japonica as a real predator

Some myrmecophilous animals show myrmecomorphy, however, its adaptive significance is still controversial. We investigated a possible benefit of Batesianmimicry between a myrmecophilous staphylinid beetle, Pella comes, and its host ant, Lasius (Dendrolasius) spathepus, by using a common ant predator, the Japanese treefrog, Hyla japonica. In the field, H. japonica were found to feed on numerous ants and other insects, but in laboratory experiments they refused feeding on L. spathepus. L. spathepus was highly repellent to these frogs, while P. comes was potentially palatable. After repeated contacts with L. spathepus which led to its avoidance the treefrogs started to reject P. comes as well . This suggests that myrmecomorphy is beneficial to P. comes, reducing the risk of predation, and that it , may represent a case of Batesian mimicry. may represent a case of Batesian mimicry. Received 15 February 2005; revised 12 April 2005; accepted 18 April 2005.