AQUATIC ENTOMOFAUNASTRUCTURE INBANCO STREAM (BANCO NATIONAL PARK, COTE DIVOIRE)

In this study, a first inventory of aquatic insect in Banco Stream, (Cote dIvoire) and the correlations between environmental variables and the abundance of the main taxa were analysed. Seven stations were sampled monthly, over a 1-year period, using a hand net (10 ?10 cm, 250 ?m mesh, 50 cm length). 118 insects were recorded. They were distributed among 61 families and eight orders. Aquatic insects richness is clearly dominated by Coleoptera (27 taxa). Chironomidae was the dominant family (76%). The highest values of Shannon-Weaver diversity and Pielous Evenness index were recorded at upstream station areas (S1 and S2).The Sorensen Similarity among stations varied from 23.53 % (S6 ? S7) to 66.67 % (S1 ? S2). Rare taxa (FO < 25%) were the most numerous (> 62%) at the different stations. Correlations between the most abundant taxa and environmental parameters using the Focused Principal Component Analysis showed a strong positive correlation between dissolved oxygen and Gomphidae and Libellulidae (Odonata). Chironomidae and Tipulidae (Diptera) abundance were positively correlated with sand.The effects of the civilian prison and other domestic wastes on aquatic insect structure can be mitigated, if this waste is properly channelled and treated before discharge into the Banco Stream.