Prelimirary survey and distribution of water beetles (Coleoptera) at Restinga de Maricá, Maricá, RJ"

Abstract

Quantitative and qualitative samples of water beetles were carried out in seven water bodies of differwnt sizes and physiognomies located at the Restinga de Maricá from January to September, 1996. A total of 65 species were collected belonging to the following families: Dytiscidae (32 spp.), Gyrinidae (1 sp.), Haliplidae (1 sp.), Hydrophilidae (22 spp.), Noteridae (8 sp.) and Scirtidae (1 sp.), Thermonectus circumscriptus, T. margineguttatus, T. succinctus, Laccophilus ovatus, Megadytes marginithorax (larva), Suphisellus sp.1 and Hydrocanthus sp. 2 were abundant and widely distributed. Larvae of M. marginithorax (in opposition to the adults) and imagines of Hydrocanthus sp.2 were the most representative in regard to the number of specimens. The factors that have most influenced the distribution of water beetles were the degree of acidity and water temperature. Some species presented association with macrophytes, like for instance: Tropisternus sp.3 with Salvinia auriculata OI' Nyniphea ampla, larvae of Celina with Eleocharis and larvae of Megadytes giganteus and M. marginithorax with Fiurena umbellata, Rhantus calidus, the species of Thermonectus and Tropisternus lateralis exhibited the highest degree of tolerance to low levels of pH.