Biological Notes on Ocypus Olen, a Predator of Brown Garden Snail, With Descriptions of the Larva and Pupa(Coleoptera: Staphylinidae)

In a recent article by Orth, Moore, Fisher, and Legner (975) laboratory studies of the snail eating habits of an adult specimen of Ocypus dens M/iller were reported. Since then there has been opportunity to conduct similar studies of sever.al larvae of the same species. The egg remains unknown. These larvae readily consumed snails, thus also demonstrating a potential or snail control. This view is urther encouraged in the Riverside garden of one of the authors (I. Moore) which has a well established population of 0. olens but a very low population of Helix aspersa Miiller (brown garden sn’ail). Other nearby gardens where O. olens appears no.t to be established have much higher population densities o.f H. aspersa. The host snail employed in our laboratory studies was Helix aspersa. In California this snail has long been considered a major agricultural and suburban pest with an omnivorous diet which includes living and decaying vegetables, flowers, ground cover, citrus leaves and fruit as well as paper labels and cardboard cartons and cadavers of its own species. The rove beetle Ocypus olens, sometimes referred to as the devil’s coach horse, is .a large (to 32 ram) black staphylinid indigenous to Europe. In North America it is kno.wn only trom California where it was first reco.rded in southern California in I93I (Orth, et al., 975). Since that time distributional records extend about six hundred miles to the north. In Ca.liornia both Ocypus olens and Helix aspersa seem to. prefer cultivated or landscaped habitats. In the field we have seen .and collected O. olens only in areas disturbed by man. This beetle therefore would seem to pose no threat to California’s native land snails, which are generally found in the undisturbed hillsides, mountains, and deserts.