Beetles (Coleoptera) of Peru: A Survey of the Families. Hydraenidae

Abstract

Diversity in Peru: 2 genera, 13 species. Recognition: Hydraenids, commonly called minute moss beetles, may be recognized by their small size (generally ,3 mm), very short nine-segmented antennae with a five-segmented club, and six or seven abdominal ventrites. Habitat: These beetles are usually found along margins of streams (especially sandy streams), but sometimes along the margins of lentic habitats (including rock pools). Adults often live interstitially among sand grains and gravel, or occupy the region just below the water surface along the shore or on half-submerged rocks. Most species can be collected by the “shore washing” method, in which water is splashed on the shoreline, and flows back into the stream or pond. Beetles are dislodged from the sand and gravel, and float to the surface, where they can be collected with a fine mesh net. Standard aquatic nets often have meshes that are too large, and the hydraenids pass through. Notes: The following list of Hydraenidae is derived from Perkins (1980, 2011). Blackwelder (1944–1957) did not list any species for Peru. There are certainly more species of Hydraenidae to be discovered in Peru.