Some aspects on faunistics and ecology of chironomidae larvae in lake Tanganyika and the Ntahangwa river
Janssens de Bisthoven, L.; Theunissen, B.; Vandelannoote, A.; Ollevier, F.P. (1993). Some aspects on faunistics and ecology of chironomidae larvae in lake Tanganyika and the Ntahangwa river. Belg. J. Zool. 123(Suppl. 1): 36-37
In: Belgian Journal of Zoology. Koninklijke Belgische Vereniging voor Dierkunde = Société royale zoologique de Belgique: Gent. ISSN 0777-6276; e-ISSN 2295-0451, more
A first contribution to the knowledge of the chironomid larvae in the Northern Bay of Lake Tanganyika and the River Ntahangwa (Burundi) is presented. In total, 32 different larval types were recovered from littoral and profundal (max. depth 64 m) ponar samples in Gitaza and Bujumbura Bay and from two series of handnet samples along the River Ntahangwa. Most genera differed by their diagnosis in some details from the diagnoses given in 'Chironomidae of the Holarctic region, Part 1 Larvae' (1). Following genera could however be recognized with certainty: Paratanytarsus, Tanytarsus, Cricotopus, Microchironomus and Polypedilum. Four genera are new to 'the catalogue of the Diptera of the Afrotropical region' (2): Paratanytarsus, Parachaetocladius, Zavrelimyia and Rheopelopia. The chironomid taxocenes are different in Lake Tanganyika and the River Ntahangwa. Three species of Polypedilum and one of Cladotanytarsus have a characteristic litoral distribution (sandy substrate), while Clinotanypus, a Chironomini genus, Microchironomus and Procladius are sublitoral (20-35 m depth) to profundal (the last two species up to 64 m depth)(fine sand, silt and mica particles). The larval densities in the lake never exceeded 200 individuals.m-2. For the River Ntahangwa we observed a spatial and temporal succession of chironomid species: the ratio Chironomini/Orthocladiinae increased steadily with increasing eutrophication downstream the river, which receives domestic sewage from the city of Bujumbura. Densities were higher during the dry season than at the beginning of the rainy season. Moreover, species dominance downstream was different in the dry and in the rainy season. Especially the oligotrophic Lake Tanganyika, of great economic and ecological value and threatened by pesticide and urban pollution, should carefully he monitored for changes in chironomid diversity and temporal and spatial patterns, as these are known to exhibit some value as pollution bioindicators.(1) T. WIEDERHaLM Ed. (1983). Ent. Scand. Suppl. Suppl. 19,pp.457.(2) P. FREEMAN and P.S. CRANSTAN (1980). Catalogue of the Diptera of the Afrotropical region. R. W .Crosskey Ed., British Museum (Nat. Hist.): 175-202.
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