Species of Culicoides breeding on rocks and riverbanks in Nigeria

Abstract

Abstract Catches of Culicoides made on a rocky hill and river bank in south‐western Nigeria showed Culicoides grahami and C.distinctipennis to be dominant. The former was most active at dusk and the latter at dawn. The number of matured eggs in the gravid female Culicoides caught on the hill and riverbank was low compared with those in gravid females of the same species caught around livestock. The fat bodies of all the dissected nulliparous and newly emerged Culicoides were full and large; those of the parous ones were depleted and inconspicuous except in individuals caught between June and July. The crop of most of the adult Culicoides contained colourless to dark yellowish fluid. C.grahami was the most numerous of the newly‐emerged species followed by C.distinctipennis. On the rocky hill, Culicoides bred in rotholes and boggy ground in between the rocks; at the river bank, breeding sites were underneath partially waterlogged canoes, in crabholes and other crevices, and underneath rotten vegetation. The influence of rainfall on the Culicoides population is discussed. Most of the species had adapted themselves to nectar feeding and autogeny was common. Perhaps some species aestivate during the hot dry season.