Aquatic insects associated with plants in two reservoirs at Ibadan, Nigeria

The insect communities of aquatic plants were studied in 2 reservoirs in Nigeria. Eleiyele reservoir had 51 insects/m2 (14 species) and Oba reservoir 59 insects/m2 (16 species). Aquatic plants sampled were Polygonum senegalense, Echinochloa stagnina, Salvinia nymphellula, Nymphaea lotus, Ceratophyllum demersum, Commelina sp., Acroceras amplecteus, Pistia stratiotes, Ipomoea ascartolia and I. aquatica. The following insect taxa were found, in order of abundance: Hemiptera > Odonata > Diptera > Ephemeroptera > Coleoptera. Among insects found were species in the genera Culex (C. pipiens), Tabanus and Chrysops, although the numerically most important were Poissonia [Hydrocyrius], Aeschna, Tendipes [Chironomus]and Plea. P. stratiotes supported the greatest number and diversity of insects of all the aquatic plants sampled.