Aquatic Insects Diversity and Water Quality Assessment of a Tropical Freshwater Pond in Benin City, Nigeria

Abstract

Aquatic insects are species of significant importance to water bodies because they serve various purposes including nutrient cycling, vectors of  pathogens and bioindicators of water quality. Analyzing their community structure is a veritable tool in studies of biodiversity and quality of limnetic  ecosystems. Therefore, we investigaTed the health status of a pond in Benin City, Nigeria using insect’s abundance, composition, distribution and physicochemical parameters of the waterbody. Insects were sampled using sweep nets and identified to the species level while water samples were collected and analyzed using in-situ and ex-situ methods to determine the physicochemical properties in three sampling stations. The results of the physicochemical assessment of the water indicated that conditions did not differ widely between sites (P > 0.05) except for total alkalinity, and the recorded values were well within the ambient FMEnv permissible limits for surface water except for dissolved oxygen,
turbidity and phosphate. A total of 10 insect taxa, comprising of 103 individuals in 2 orders were recorded in the study and among the orders, Hemiptera comprised of 7 species and Coleoptera comprised of 3 species. Majority of the insect fauna found in this study are typically found in similar water bodies in the tropics. However, the obsereved insect community structure revealed a relatively low taxa richness with a dominance of pollution-resistant species which suggests a moderately polluted condition of the waterbody.

Keywords: Aquatic insects, bioindicators, biodiversity, water quality, pond.