Aspectos da biologia de Buenoa platycnemis (Fieber) (Insecta, Heteroptera, Notonectidae) da Restinga de Maricá, Rio de Janeiro

Abstract

ABSTRACT. On the biology of Buenoo plotycnemis (Fieber) (Insecta, Heteroptera, Notonectidae) at Restinga de Maricá, Rio de Janeiro State, Brazil. A month1y quantitative study on B. platycnemis (Fieber, 1851) was carried out in a sand dune marsh, on the littoral ofRio Janeiro State. The aims ofthis study were to correlate the life cycle ofthe species with lhe seasonal regime ofthe water body, defining steps of the annual cycle, age structure, and to indicate oviposition sites and trophic relalions. The species shows a marked seasonal tendency . The major steps of the life cycle obtained were an invernal (weak) with a predominance of imagines, followed by another of population expansion, characlerized by lhe absence of adults, massive eclosions and predominance of low instar nymphs. Probably, B. pla/ycnemis has a sensibility to water levei varialion and might be influenced by the concentration of Spirogyra sp. (Chlorophyceae) in the water column. ln relation to oviposition, B. platycnemis has not shown preference for any macrophyle, since eggs were found in Rhynchosphora corymbosa (Linnaeus) Britton (Cyperaceae), Eleocharis sel/owiana Kunth. (Cyperaceae) andNy mphoides indica (Linnaeus) O. Kuntze . (Menyanthaceae). The observed predators of B. platycnemis were Anax amazilli (Burmeister, 1839) (Aeshinidae), Erythemis credula (Hagen, 1861) (Libellulidae) and other Odonata, nymphs and adults of Belostoma candidulum Montandon, 1903 (Belostomatidae), Notonecta (Paranecta) dis/urbata Hungerford, 1926, Buenoa antigone antigone (Kirkaldy, 1899) (Notonectidae), besides Curicta cf tibialis (Martin, 1898) and Ranatra horvathi Montandon, 1910 (Nepidae). Larvae of Sayomyia sp. (Chaoboridae), Chironomus spp. and Labrundinia sp. (Chironomidae), Cal/ibaetis guttatus Navás, 1915 (Baetidae), cladocerans and copepods are potential prey of B. platycnemis, while ostracodes were refused .