DIVERSITY AND ABUNDANCE OF AQUATIC INSECTS IN DAN ZARIA RESERVOIR, GIDAN KWANO CAMPUS, MINNA, NIGER STATE.

Aquatic insects represent an integral part of freshwater ecosystem and they contribute to various ecological services in the ecosystem. This study conducted on Dan Zaria Reservoir by evaluating the community structure of aquatic insects. Field sampling was carried out over four months at four distinct stations (ST1, ST2, ST3, ST4). Aquatic insects were collected using a sweep net, identified, and counted. Water samples were analyzed for pH, Electrical Conductivity (EC), Temperature, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Nitrate (NO₃), Total Alkalinity (TA), Total Hardness (TH), and Calcium (Ca) using standard methods. Data were subjected to descriptive statistics; diversity indices and Canonical Correspondence Analysis (CCA) were calculated. The results revealed a total abundance of 308 individual insects, distributed across 8 taxa. Odonata was the most prominent order, with Dragonfly Larvae being the most abundant taxon (50 individuals), followed by Damselfly Larvae (47). Spatially, total abundance was highest at ST1 (107) and lowest at ST4 (52). Diversity indices were consistently high across all stations; the Shannon-Wiener Index (H') ranged from 2.0009 (ST3) to 2.0417 (ST4), Pielou's Evenness (J) exceeded 0.96 at all sites, and the Simpson Index (1-D) ranged from 0.8572 to 0.8654. Physicochemical results showed minimal spatial variation, with a pH range of 6.62 - 6.72 and DO between 6.58 - 11.38 mg/L. Temporal analysis revealed a critical drop in DO to 5.63 mg/L in one month, concurrent with a steady increase in BOD from 0.26 mg/L to 2.00 mg/L over the four-month period. Multivariate analysis (CCA). In conclusion, Dan Zaria Dam supports a diverse and evenly distributed aquatic insect community, indicating a currently stable ecosystem.