Rove beetles (Coleoptera: Staphylinidae) in Neotropical riverine landscapes: characterising their distribution

The diversity and ecology of Staphylinidae in the Neotropical region has been poorly investigated, especially in riverine landscapes where these beetles are among the dominant organisms. Therefore, the relation between the occurrence of Staphylinidae and environmental variables was investigated in riverine systems of Southwest and Central Colombia. Samples were collected between 1984 and 2006 following standardised methods for biological sampling and water quality evaluation. Water quality indexes were calculated and six microhabitats were surveyed: riparian vegetation (light traps), sediments (surber net), rock, macrophytes and litter (manually). The 1834 collected individuals belonged to seven subfamilies and 17 genera. The most frequent genera were Thinodromus, Stenus and Philonthus. Among all measured environmental variables, microhabitat explained to most extent the distribution patterns of the rove beetles. Preference to riparian vegetation was found for the family as a whole but preferences by subfamilies differed strongly. Steninae were absent in the riparian vegetation and showed close association to macrophytes. Oxytelinae and Staphylininae were frequently collected in riparian vegetation and litter, respectively. Although water quality and altitude were only of secondary importance to the Staphylinidae distribution, the tolerance of Steninae to waters of poorer quality and its concentration in the altitudinal range of 1001-1500 m a.s.l. is highlighted. Preferences to certain microhabitats found for some Staphylinidae taxa supply more evidence to the habitat-specialisation of these beetles, representing an important contribution to both their ecological characterisation and to the fauna of riverine systems in the Neotropical region.