With the aim of studing the composition of Chironomidae fauna and other aquatic insects of São José dos Cordeiros dam, in São José dos Cordeiros -PB (07º 23'S e 36º 49'W), bimonthly qualitative samples were colected between July/1998 and July/1999. The insect fauna was sampled randomly with one hand net of 0.50 mm mesh size. The material collected was fixed in formol 10%, the triagem was made through illuminated tray and for identification was used a stereomicroscope. Some physical and chemical water parameters were determined to correlated with biological data. Aedokritus was the dominating and more frequent genera of Chironomidae in mud of dam, showing the maximum abundance of 94.47% in January/99. On the other hand Dicrotendipes sp3 was only found in July/98 (12.50% of the total aquatic insects fauna). Beyond of Chironomidae, the occurrence of Ceratopogonidae (Diptera), Gomphidae (Odonata), Coleoptera and Campsurus sp. (Polymitarcyidae, Ephemeroptera) was observed. The abundance of all Chironomidae genera was significantly corraleted with the organic matter of sediment. During the period of September/98 to January/99 was observed an increase in the percentual organic matter in sediment that corresponded to the increase in the abundance of Aedokritus sp. and a consequently decrease in the abundance of Gomphidae. Therefore, changing in physical and chemical conditions of water mainly associated to the increase in organic matter may produce a consequently decrease in the biomass of the aquatic insects.
Chironomidae; Aedokritus sp; aquatic insects; semi-arid
