New Distributional Records for Platystethus (Coleoptera: Staphylinidae: Oxytelinae) with Notes on the Biology of P. americanus
A survey of the fauna of cattle dung dropped naturally on pasture in Alachua County, Florida, revealed several species of Staphylinidae, including two species of Platystethus. Adult Platystethus spiculus Erichson were collected only in July 1991. Adult Platystethus americanus Erichson were collected from March to June 1993. In the laboratory, immature stages of P. americanus took 18-22 days to develop at 27oC (2-3, 10-12, and 7 days for the egg, larval, and pupal stage, respectively). Some adults were offered cattle dung alone as diet in which the females deposited eggs in chambers. Some larvae were offered cattle dung and horn fly [Haematobia irritans (L.)] larvae as diet, and the beetle larvae pupated successfully in chambers or partial chambers under the dung. Adults and larvae held without cattle dung ate horn fly larvae, but females did not oviposit and beetle larvae did not pupate, most likely because they require dung or a similar substrate in which to make chambers. New distributional records are Florida and New Mexico for P. americanus, and St. Croix (U.S. Virgin Islands) and New Mexico for P. spiculus.