ABSTRACT
Aquatic insects are hexapods that either live or spend part of their life cycle in water bodies. They play crucial roles contributing to nutrient cycling and as bioindicators of water quality. The community composition of aquatic insects in Eruvbi Stream, Benin City, Nigeria, was investigated from March to May 2023. Insects were collected using sweep nets and identified to the species level, while water samples were analyzed both in-situ and ex-situ to assess physicochemical properties at three different sampling stations. The physicochemical analysis revealed no significant differences between most of the stations except for suspended solids, turbidity, sulphate, phosphate, and biological oxygen demand, which showed significant difference (P<0.05). The study identified a total of 510 individuals across 12 taxa from five insect orders, with Diptera being the most abundant, particularly with chironomous spp. being predominant at all stations. Hemiptera and Odonata were also notable, with relative abundances of 26.275% and 23.529% respectively, while Coleoptera was represented by Dysticus marginalis and Trichoptera represented by Hesperophylax sp., which was the least common, appearing only twice at Station 1. The diversity index indicated that Station 1 had the highest taxa richness and diversity, whereas Station 2 had the lowest, this is attributed to the detrimental effects of physical and biological water quality degradation. This study concludes that industrial effluent discharge into Eruvbi Stream adversely impacts water quality, affecting the distribution, abundance, and diversity of aquatic insects.
