Bionomia de Odonata (insecta) em dois igarapés da Reserva Florestal Adolfo Ducke (Manaus-AM-Brasil)

Abstract

The study was carried out from May 1995 to April 1996, and consisted in monthly observations in two stream in the Adolfo Ducke, Forest Reserve, 26 km SE from Manaus, Amazonas, Brazil. Thirty six samples were taken along 2,000 m of each stream, beginning at the headwaters, in order to study the community structure, temporal and spatial changes in adult and larval populations, substrate preferences and associations among larvae. A total of 28 taxa of adu,lt Odonata, and 24 taxa of larvae were found. The similarity indices between the two streams were 0,92 and 0,84, for adults and larvae, respectivel. Seasonal differences in the abundance of adults and larvae were not detected for cornmunity (Mann-Whitney; P>0.05), nor was a depth effect on larval distribution found (Kruskal-Wallis; P>0.05). However, the data suggest seasonality and spatial effects on the behavior of adults and larvae. Although substrate preferences was statistically diferente for a stream (Kruskal-Wallis; P<0.05), some species were Only caught in one type of substrate. Association of larvae using Cluster Analysis revealed two groups, based on substrate type.