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Species composition and cyclical changes in numbers of savanna blackflies (Diptera: Simuliidae) caught by suction traps in the Onchocerciasis Control Programme area of West Africa

Published online by Cambridge University Press:  10 July 2009

C. G. Johnson
Affiliation:
42 Luton Road, Harpenden, Herts AL3 2UJ, UK
R. W. Crosskey
Affiliation:
Department of Entomology, British Museum (Natural History), Cromwell Road, London SW7 5BD, UK
J. B. Davies*
Affiliation:
℅ Department of Medical Entomology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
*
* Name and address for correspondence.

Abstract

Ten large suction traps were operated continuously, day and night, throughout the wet season of 1977 at four widely separated places within the area of the Onchocerciasis Control Programme in the Volta River Basin (OCP) in West Africa. At least ten species of Simulium s.l. were trapped and the daily catches were analysed qualitatively and quantitatively. In the total catch of 9189 flies there were 187 males and 9002 females; among the latter only six were gravid and only five contained a full blood-meal. Cyclical changes in numbers, with periodicities ranging from 10 to 20 days, were analysed in series of overlapping Gaussian distributions, each possibly reflecting the rise and fall of a distinct population. Similar patterns in the sequence of cycles were shown by S. adersi Pomeroy, S. ruficorne Macq., S. evillense Fain, Hallot & Bafort and other species at a particular trapping site. Patterns differed between catching sites, except in the general tendency for population maxima to increase during the season. In some species, notably S. adersi, populations decreased in late July and early August before increasing greatly in September (end of the rains) prior to the October onset of the dry season. Among the species caught, S. evillense was present at all four trapping sites and particularly abundant at two of them, although the species has never been recorded before in West Africa and its early stages remain undiscovered there despite special searches for them since the capture of adult flies. By contrast, only four specimens of S. hargreavesi Gibbins were trapped although this species is abundant in local breeding sites. Diel flight periodicity was recorded over a one-week period at the extreme end of the wet season and showed that most flies were caught in the daytime; S. ruficorne showed a greater tendency to a unimodal periodicity than other species. The behaviour of flies at the time of capture is discussed, including a consideration of the local wind speeds and the air speed of Simulium s.l.

Type
Research Paper
Copyright
Copyright © Cambridge University Press 1982

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References

Cassie, R. M. (1954). Some uses of probability paper in the analysis of size frequency distributions.—Aust. J. mar. Freshwat. Res. 5, 513522.CrossRefGoogle Scholar
Cooter, R. J. (1981). Studies of the flight of Simulium species. 1. Flight performance of S. ornatum Mg.—61 pp. Unpublished document World Health Organization No. 08/181/13 and Centre for Overseas Pest Research No. 192/152/05.Google Scholar
Crosskey, R. W. (1980). Family Simuliidae.—pp. 203210in Crosskey, R. W. (Ed.). Catalogue of the Diptera of the Afrotropical Region.—1437 pp. London, British Museum (Natural History).Google Scholar
Davies, L. (1961). Ecology of two Prosimulium species (Diptera) with reference to their ovarian cycles.—Can. Ent. 93, 11131140.CrossRefGoogle Scholar
Davies, L. & Williams, C. B. (1962). Studies on black flies (Diptera: Simuliidae) taken in a light trap in Scotland. I. Seasonal distribution, sex ratio and internal condition of catches.—Trans. R. ent. Soc. Lond. 114, 120.Google Scholar
Dry, W. W. & Taylor, L. R. (1970). Light and temperature thresholds for take-off by aphids. —J. Anim. Ecol. 39, 493504.CrossRefGoogle Scholar
El Bashir, S., El Jack, M. H. & El Hadi, H. M. (1976). The diurnal activity of the chicken-biting black fly, Simulium griseicolle Becker (Diptera, Simuliidae) in northern Sudan.—Bull. ent. Res. 66, 481487.CrossRefGoogle Scholar
Fain, A., Hallot, R. & Bafort, J. (1966). Un nouveau Simulium du Katanga.—Revue Zool. Bot. afr. 74, 205208.Google Scholar
Fraser, R. D. B. & Suzuki, E. (1973). The use of least squares in data analysis.—in Leach, S. J. (Ed.). Physical principles and techniques of protein chemistry. Part C.—621 pp. New York & London, Academic Press.Google Scholar
Freeman, P. & De Meillon, B. (1953). Simuliidae of the Ethiopian Region.—224 pp. London, British Museum (Natural History).Google Scholar
Garms, R., Walsh, J. F. & Davies, J. B. (1979). Studies on the reinvasion of the Onchocerciasis Control Programme in the Volta River Basin by Simulium damnasum s.l. with emphasis on the south-western areas.—Tropenmed. & Parasitol. 30, 345362.Google Scholar
Glick, P. A. (1939). The distribution of insects, spiders, and mites in the air.—Tech. Bull. U.S. Dep. Agric. no. 673, 150 pp.Google Scholar
Hansford, R. G. & Ladle, M. (1979). The medical importance and behaviour of Simulium austeni Edwards (Diptera: Simuliidae) in England.—Bull. ent. Res. 69, 3341.CrossRefGoogle Scholar
Hocking, B. (1953). The intrinsic range and speed of flight of insects.—Trans. R. ent. Soc. Lond. 104, 223346.Google Scholar
Johnson, C. G. (1969). Migration and dispersal of insects by flight.—763 pp. London, Methuen.Google Scholar
Johnson, C. G. & Taylor, L. R. (1955). The development of large suction traps for airborne insects.—Ann. appl. Biot. 43, 5162.CrossRefGoogle Scholar
Le Berre, R. (1966). Contribution à l'étude biologique et écologique de Simulium damnosum Theobald, 1903 (Diptera, Simuliidae).—Mém. O.R.S.T.O.M. no. 17, 204 pp.Google Scholar
Le Berre, R. & Wenk, P. (1967). Beobachtungen über das Schwarmverhalten bei Simulium damnosum (Theobald) in Obervolta und Kamerun.—Verh. dt. zool. Ges. 1966 (= Zool. Anz. 30, Suppl.), 367372.Google Scholar
Lewis, T. & Taylor, L. R. (1964). Diurnal periodicity of flight by insects.—Trans. R. ent. Soc. Lond. 116, 393469.CrossRefGoogle Scholar
Lewis, T. & Taylor, L. R. (1967). Introduction to experimental ecology.— 401 pp. London & New York, Academic Press.Google Scholar
Reuben, R. (1963). A comparison of trap catches of Culicoides impunctatus Goetghebuer (Diptera: Ceratopogonidae) with meteorological data.—Proc. R. ent. Soc. Lond. (A) 38, 181193.Google Scholar
Service, M. W. (1971 a). Adult flight activities of some British Culicoides species.—J. med. Entomol. 8, 605609.CrossRefGoogle ScholarPubMed
Service, M. W. (1971 b). Flight periodicities and vertical distribution of Aedes cantans (Mg.), Ae. geniculatus (Ol.), Anopheles plumbeus Steph. and Culex pipiens L. (Dipt., Culicidae) in southern England.—Bull. ent. Res. 60, 639651.CrossRefGoogle Scholar
Service, M. W. (1973). Observations on the flight activities of Chrysops caecutiens L.— Ann. trop. Med. Parasit. 67, 445454.CrossRefGoogle ScholarPubMed
Service, M. W. (1977). Methods for sampling adult Simuliidae, with special reference to the Simulium damnosum complex.—Trop. Pest Bull. no. 5, 48 pp.Google Scholar
Southwood, T. R. E. (1978). Ecological methods with particular reference to the study of insect populations. Ed. 2.—524 pp. London, Chapman & Hall.Google Scholar
Taylor, L. R. (1955). The standardization of air-flow in insect suction traps.—Ann. appl. Biol. 43, 390408.CrossRefGoogle Scholar
Taylor, L. R. (1958). Aphid dispersal and diurnal periodicity.—Proc. Linn. Soc. Lond. 169, 6773.Google Scholar
Taylor, L. R. & Carter, C. I. (1961). The analysis of numbers and distribution in an aerial population of Macrolepidoptera.—Trans. R. ent. Soc. Lond. 113, 369386.CrossRefGoogle Scholar
Walsh, J. P., Davies, J. B. & Le Berre, R. (1979). Entomological aspects of the first five years of the Onchocerciasis Control Programme in the Volta River Basin.— Tropenmed. & Parasitol. 30, 328344.Google ScholarPubMed
Walsh, J. F. & Garms, R. (1980). The detection of plant sugars in Simulium damnosum s.1. by means of the cold Anthrone test.—Trans. R. Soc. trop. Med. Hyg. 74, 811813.CrossRefGoogle Scholar
Williams, C. B. (1965). Black-flies (Diptera: Simuliidae) in a suction trap in the Central Highlands of Scotland.—Proc. R. ent. Soc. Lond. (A) 40, 9295.Google Scholar
Williams, C. B. & Davies, L. (1957). Simuliidae attracted at night to a trap using ultraviolet light.—Nature, Lond. 179, 924925.CrossRefGoogle ScholarPubMed