Diversity of Insects Associated with Decaying Organic Matter in Port Harcourt, Rivers State, South South Nigeria

This study documents the diversity of insects associated with decaying organic matter at waste dump sites and compost piles in Port Harcourt, Rivers State, located in Nigeria's South South geopolitical zone. Insects involved in decomposition are ecologically important as nutrient recyclers and are of forensic and public health significance, yet their community diversity at organic waste sites in major Nigerian cities is poorly documented. Using a descriptive sampling design, insects were collected from four waste sites using pitfall traps, berlese funnels, and hand sorting over three months covering dry and wet seasons. Adult insects and larvae were identified to family or genus level. Environmental variables were recorded at each site. A total of 48 insect species from 12 orders and 31 families were recorded. Diptera (22 species) dominated, followed by Coleoptera (13 species) and Hymenoptera (8 species). Calliphora vomitoria, Chrysomya albiceps, and Lucilia cuprina were the most abundant fly species. Staphylinidae and Dermestidae dominated the Coleoptera assemblage. Species richness and abundance were significantly higher at open food waste dumps than at enclosed compost heaps. Wet season collections yielded greater abundance but lower diversity than dry season. The study provides a baseline invertebrate decomposer dataset for Port Harcourt and highlights public health risks from blow fly proliferation at unmanaged urban waste sites, recommending enclosed composting infrastructure as a health and biodiversity improvement measure. Keywords: insect diversity, decomposition, organic matter, Port Harcourt, Diptera.