Composition and microhabitat preferences of Odonata (Insecta) immatures in a lowland section of the Rio Ubatiba, Maricá-RJ, Brazil. Monthly sampling was held from May, 1999 to May, 2000 in the Rio Ubatiba, a lowland river situated at Maricá district, Rio de Janeiro State, Brazil. Seven different substrates were collected along fifty meters. A total of 1,279 larvae of Odonata were collected and identified in 27 species, belonging to five families. The most numerous species were Acanthagrion lancea (Selys, 1876), Hetaerina auripennis (Burmeister, 1839), Micrathyria hesperis Ris, 1911 and Telebasis filiola (Perty, 1834). The greatest number of individuals were found in "riparian plants in depositional areas". In general, the species recorded showed habitat preferences: Dythemis multipunctata Kirby, 1894, Erythrodiplax sp., M. hesperis, T. filiola, A. lancea, Erythemis sp., Coryphaeschna adnexa (Hagen, 1861) and H. auripennis seem to prefer organic substrates and Brechmorhoga sp., B. praeCOX (Hagen, 1969) and Progomphus complicatus Selys, 1854, inorganic substrates.
Immature stages; lowland streams; Odonata; Southeastern Brazil; substrate preferences
