Estudo da distribuição espaço-temporal da comunidade de larvas de Trichoptera Kirby, 1813 (Insecta) em um tributário de primeira ordem do rio Paquequer, Teresópolis, RJ

Abstract

Study of the spatial and temporal distribution of the Trichoptera (Insecta) larvae community in a first order tributary of the Paquequer river, Teresópolis, RJ. The Trichoptera fauna was sampled in a first order tributary of rio Paquequer, in the district of Teresópolis, Rio de Janeiro State. Quantitative samples of litter from pools, litter from riffles, sand and stones were taken on each season, from February 1991 to February 1992. An amount of 2582 larvae were found, totalizing 10.4 g weight. Nine families and twenty genera were identified. Litter from pools supported the highest frequency of larvae per substrate whereas summer 1992 and winter presented the highest frequencies of larvae among seasons. The results of correspondence analysis showed that discharge and detritus quality influence primarily the spatial distribution of Trichoptera community. The life cycles of common genera were categorized into three group of biological strategies. The largest group represented the general type of the community, where latest instar were predominant in spring and the earliest in summer. Probably, emergency and oviposition occur in spring. The trophic functional categories of Trichoptera beared a close relationship to substrate type: the maximum values of frequency and biomass were highest for shredders on litter from pools, collectors on litter from riffles, predators on sand and scrapers on stones.