Diversity and seasonal pattern of Chironomidae (Insecta; Diptera) in seven lotic systems of Southeast Côte d'Ivoire

This study aimed to evaluate the spatial and seasonal variation of the richness and abundance of Chironomidae larvae and related its distribution to physical and chemical variables in seven lotic systems of Southeast Cote d’Ivoire. Two sampling stations were retained in each system. Chironomidae were sampled at two occasions during each season using a triangular hand net (10 X 10 X 10 cm, 250 µm mesh, 50 cm length). Thirteen genera were identified in three subfamilies (Chironominae, Tanypodinae and Orthocladiinae). Chironominae, with 67.75% of the relative abundance, was the most diversified subfamily, followed by Tanypodinae (23.27%) and Orthocladiinae (9.23%). Agneby River contained the most diversified community with eleven genera, whereas the least diversified was encountered in Bia River (7 genera). Polypedilum and Tanytarsus were the dominant taxa in the study area. Genus richness was in general higher in rainy season in rivers Agneby and Bia, while it was higher in dry season in the others streams. The correspondence analysis revealed that substrate characteristics, current flow, and water mineralization level were the major factors acting upon the chironomid communities. Chironomidae can be used as a potential instrument in future ecology studies in lotic systems of Southeast Cote