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Comparative studies on sibling species of the Anopheles gambiae Giles complex (Dipt., Culicidae): bionomics and vectorial activity of species A and species B at Segera, Tanzania*

  • G. B. White (a1), S. A. Magayuka (a2) and P. F. L. Boreham (a3)

Extract

Collections of Anopheles gambiae Giles complex, A. funestus Giles group and other mosquitoes were made by spray-catch from twelve catching stations indoors and by hand-catch from pit shelters at two catching stations at Segera, Tanzania, between January 1970 and June 1971. Females of A. gambiae were identified cytotaxonomically as sibling species A or B of the complex. In houses during 1970, A. gambiae species B was more numerous at first than A, but A became predominant during the long rains of March-May. In the cool dry weather of June-November both A and B densities declined and the A:B ratio surpassed 50:1. The short rains in December produced a population explosion of species B and less multiplication of species A, the B:A ratio reaching >11:1. In 1971, hot dry weather during January-March caused declines of species A and B with a maximum B: A ratio of 13:1. Long rains, coming in late March, provoked a resurgence of A and a concurrent decline of B, so that the A:B ratio again reached 20:1 in June. Similar cycles of species A and B were observed outdoors, although the relative numbers outdoors/indoors averaged 2·3 times more for species B than for species A. In A. funestus, A. gambiae species A and A. gambiae species B Human Blood Indices were 97·5%, 91·2% and 60·9% indoors and 24%, 2% and 7% outdoors, respectively. Respective malaria sporozoite rates were 1·62%, 4·23% and 0·32% and minimum rates of stage-Ill filarial infection were 0·33%, 0·44% and 0·57%. Sporozoite-positive and sporozoite-negative mosquitoes exhibited similar HBF's in species A and discrepant HBI's in species B. The HBI's were higher in filariapositive A and B females than in filaria-negative females. Gregarines occurred in 1·36% of species A and 0·38% of species B. Trematode cysts were seen in two specimens of species A.

Of A and B females 28% and 4%, respectively, had four-banded palps. It is shown mathematically that the discrepant malaria sporozoite rates in species A and B may be explained by extrapolating from the man-biting rate and probable daily survival rate for each species. This implies that no unrecognised factors play a major role in causing the contrasting efficiency of these two sibling species as malaria vectors.

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References

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Bartram, D. S. (1971). Trop. Dis. Bull. 67, Abstr. 504, 236237.
Chauvet, G. (1969 a). Répartition et écologie du complexe Anopheles gambiae à MadagascarCah. Off. Rech. scient. tech. Outre-Mer (Ent. méd. Parasit.) 7, 235275.
Chauvet, G. (1969 b). Etudes, en particulier au moyen de radioisotopes, sur I'éthologie et la physiologie comparées des esp`eces A et B du complexe A nopheles gambiae dans une zone de sympatrie à Madagascar.—Cah. Off. Rech. scient. tech. Outre-Mer (Ent. méd. Parasit.) 7, 6191.
Chauvet, G., Davidson, G. & Coz, J. (1969). Le complexe Anophèles gambiae en Afrique continentale et à Madagascar.—Cah. Off. Rech. scient. tech. Outre-Mer (Ent. méd. Parasit.) 7, 912.
Clyde, D. F.(1967). Malaria in Tanzania.—167 pp. London, Oxford University Press.
Coluzzi, M. (1965). Biological observations on the Anopheles gambiae complex.—Cah. Off. Rech. scjenf. tech. Outre-Mer (Ent. méd. Parasit.) 3, 183184.
Coluzzi, M. (1966). Osservazioni comparative sul cromosoma X nelle specie A e B del complesso Anopheles gambiae.—Atti Accad. naz. Lincei Rc. 40, 671678.
Coluzzi, M. (1968). Cromosomi politenici delle cellule nutrici ovariche nel complesso gambiae del genere Anopheles.—Parassitologia 10, 179183.
Coluzzi, M. & Sabatini, A. (1967). Cytogenetic observations on species A and B of the Anopheles gambiae complex.—Parassitologia 9, 7388.
Coz, J. & Brengues, J. (1967). Le complexe Anopheles gambiae et l'épidémiologie du paludisme et de la filariose de Bancroft en Afrique de 1'Ouest.—Méd Afr. noire 14, 301303.
Coz, J. & Hamon, J. (1964). Le complexe Anopheles gambiae en Afrique Occidentale.—Riv. Molar. 43, 233244.
Cuellar, C. B. (1969). A theoretical model of the dynamics of an Anopheles garnbiae population under challenge with eggs giving rise to sterile males.—Bull. Wld Hlth Org. 40, 205212.
Davidson, G. (1962). Anopheles gambiae complex.—Nature, Lond. 196. 907.
Davidson, G. (1964 a). Anopheles gambiae, a complex of species.—Bull. Wid Hith Org. 31, 625634.
Davidson, G. (1964b). The five mating-types in the Anopheles gambiae complex.—Riv. Malar. 43, 167183.
Davidson, G. (1964c). Anopheles garnhiae, a complex of species.—Bull. Wid Hlth Org. 31, 625634.
Davidson, G. (1967). A distribution map of the member species of the Anopheles gambiae complex.—Trans. R. Soc. trop. Med. Hyg. 61, 454.
Davidson, G. (1969). The potential use of sterile hybrid males for the eradication of member species of the Anopheles gambiae complex.—Bull. Wid Hlth Org. 40, 221228.
Davidson, G. & Draper, C. C. (1953). Field studies of some of the basic factors concerned in the transmission of malaria.—Trans. R. Soc. trop. Med. Hyg. 47, 522535.
Davidson, G., Odetoyinbo, J. A., Colussa, B. & Coz, J. (1970). A field attempt to assess the mating competitiveness of sterile males produced by crossing two member species of the Anopheles gambiae complex.—Bull. Wid Hith Org. 42, 5567.
Davidson, G., Paterson, H. E., Coluzzi, M., Mason, G. F. & Micks, D. W. (1967). The Anopheles gambiae complex. In Wright, J. W. & Pal, R.Eds. Genetics of insect vectors of disease. 211250. Amsterdam, Elsevier.
Dobzhansky, T. (1951). Genetics and the origin of species. (3rd ed.).—364 pp. New York, Columbia University Press.
Draper, C. C. & Smith, A. (1957). Malaria in the Pare area of N.E. Tanganyika. Part I: Epidemiology.—Trans. R. Soc. trop. Med. Hyg. 51, 137151.
Gillies, M. T. (1954). The recognition of age-groups within populations of Anopheles gambiae by the pre-gravid rate and the sporozoite-rate.—Ann. trop. Med. Parasit. 48, 5874.
Gillies, M. T. (1964). The role of secondary vectors of malaria in north-east Tanganyika.—Trans. R. Soc. trop. Med. Hyg. 58, 154158.
Gillies, M. T. & de Meillon, B. (1968). The Anophelinae of Africa south of the Sahara (Ethiopian zoogeographical region). 2nd edn.—Publs S. Afr. Inst. med. Res. no. 54, 343 pp.
Gillies, M. T. & Wegesa, p. (1963). Infraspecific forms of freshwater Anopheles gambiae.—Rep. E. Air. Inst. Malar. 19621963, 89.
Gillies, M. T. & Wilkes, T. J. (1965). A study of the age-composition of populations of Anopheles gambiae Giles and A. funestus Giles in north-eastern Tanzania.—Bull. ent. Res. 56, 237262.
Green, C. A. (1972). The practical problem of identifying members of the A. gambiae complex in autecological studies.—Parassitologia 14, (in press).
Jordan, P. (1956). Filariasis in the Eastern, Tanga and Northern Provinces of Tanganyika.—E. Air. med. J. 33, 225233.
Kinodon, J. Ed. (1971). Atlas of East African mammals. Vol. 1.—446 pp. London, Academic Press.
MacDonald, G. (1957). The epidemiology and control of malaria.—201 pp. London, Oxford University Press.
Muirhead-Thomson, R. C. (1951). Studies on salt-water and fresh-water A nopheles gambiae on the East African coast.—Bull. ent. Res. 41, 487502.
Nelson, G. S., Heisch, R. B. & Furlong, M. (1962). Studies in filariasis in East Africa. II. Filarial infections in man, animals and mosquitoes on the Kenya coast.—Trans. R. Soc. trop. Med. Hyg. 56, 202217.
OderoYinbo, J. A. & Davidson, G. (1968). The Anopheles gambiae complex and its role in the malaria transmission in the islands of Zanzibar and Pemba, United Republic of Tanzania.—WHO/Mal/68.660 and WHO/VBC/68.89. mimeo.
Omer, S. M. & Cloudsley-Thompson, J. L. (1970). Survival of female Anopheles gambiae Giles through a 9-month dry season in Sudan.—Bull. Wid Hith Org. 42, 319330.
Pringle, G. (1966). A suggestion from declining Anopheline infection rates that socio economic factors may be reducing malaria transmission in a coastal area of Tanzania.—Rep. E. Air. inst. Malar. 1965, 2526.
Ramsdale, C. D. & Fontaine, R. E. (1970). Ecological investigations of Anopheles gambiae and Anopheles funestus. I. Dry season studies in villages near Kaduna, Nigeria—1970.—WHO/VBC/70.248 and WHO/Mal/70.735 mimeo.
Service, M. W. (1970 a). Identification of the Anopheles gambiae complex in Nigeria by larval and adult chromosomes.—Ann. trop. Med. Parasit. 64, 131136.
Service, M. W. (1970b). Ecological notes on species A and B of the Anopheles gambiae complex in the Kisumu area of Kenya.—Bull. ent. Res. 60, 105108.
Van Thier, P. H. (1954). Trematode, gregarine and fungus parasites of Anopheles mosquitoes.—J. Parasit. 40, 271279.
Wegesa, P. (1966). Further notes on the distribution of intraspecific forms of freshwater Anopheles gambiae in Tanzania.—Rep. E. Afr. Inst. Malar. 1965, 3839.
Weitz, B. (1956). Identification of blood meals of blood-sucking arthropods.—Bull. Wid Hith Org. 15. 473490.
White, G. B. (1968). The Anopheles gambiae complex.—Rep. B. Air. Inst. Malar. 1968, 3334.
White, G. B. (1969 a). The Anopheles gambiae complex.—Rep. E. Air. inst. Malar. 1969, 3134.
White, G. B. (1969 b). Parasitic protozoans from anopheline salivary glands.—Rep. E. Air. Inst. Malar. 1969, 3436.
White, G. B. (1971 a). Studies on transmission of Bancroftian filariasis in north-eastern Tanzania.—Trans. R. Soc. trop. Med. Hyg. 65, 819829.
White, G. B. (1971b). Chromosomal evidence for natural inter-specific hybridization by mosquitoes of the Anopheles gambiae complex.—Nature, Lond. 231, 184185.
White, G. B. (1972). The Anopheles gambiae complex and malaria transmission around Kisumu. Kenya.—Trans. R. Soc. trop. Med. Hyg. 66, 572581.
White, G. B. & Muniss, J. N. (1970). General surveys in East Africa of sibling species belonging to the Anopheles gambiae complex.—Rep. E. Afr. Inst. Malar. 1970.
White, G. B. & Rosen, P. (in press). Comparative studies on sibling species of the Anopheles gambiae Giles complex (Diptera, Culicidae): ecology of species A and B around Kaduna, Nigeria, during transition from wet to dry season.—Bull. ent. Res.
WHO (1963). Practical entomology in malaria eradication.—Geneva. mimeo.
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Bulletin of Entomological Research
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