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Optimized simulation of the control of tsetse flies Glossina pallidipes and G. m. morsitans (Diptera: Glossinidae) using odour-baited targets in Zimbabwe

Published online by Cambridge University Press:  09 March 2007

J.W. Hargrove*
Affiliation:
9 Monmouth Road, Avondale, Harare, Zimbabwe
*
*Fax: 263 4 308042 E-mail: john@zappuz.co.zw

Abstract

In 1984–1985 insecticide-treated targets were deployed in the 600-km2 Rifa Triangle, Zambezi Valley, Zimbabwe. Trap catches of Glossina pallidipes Austen were modelled using a function combining logistic growth with diffusive movement. A simulation routine was linked to a non-linear least-squares optimization programme and fits optimized with respect to population carrying capacities, rates of growth and movement, and to levels of imposed mortality. In March–September 1984, the overall additional mortality was 2% per day of adult female G. pallidipes, increasing thereafter to 8% per day, due to the deployment of more targets, the onset of the hot, dry season and the ground-spraying of the adjoining Zambezi escarpment with DDT. For G. m. morsitans Westwood the corresponding estimates were 1 and 2% per day. For both species, the deployment of four targets km−2 in a closed population will ensure eradication. For G. m. morsitans a halving of target efficacy would reduce the killing rate to the point where eradication would be unlikely. Estimated daily displacements were c. 200 m for G. m. morsitans and 660 m for G. pallidipes. The lower rate for G. m. morsitans means that, while targets kill this species less effectively, re-invasion of cleared areas is slower. Targets do not markedly affect robust populations outside the deployment area. The Zambian tsetse population adjacent to the Rifa Triangle declined markedly during the experiment, however, suggesting that it is largely maintained by immigration. The methods developed here will be applied to data from other campaigns with the aim of improving the efficiency of tsetse control programmes.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2003

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References

Brightwell, R., Dransfield, R.D., Stevenson, P. & Williams, B. (1997) Changes over twelve years in the populations of G. pallidipes and Glossina longipennis (Diptera: Glossinidae) subject to varying trapping pressure at Nguruman, south west Kenya. Bulletin of Entomological Research 87, 349370.CrossRefGoogle Scholar
Dransfield, R.D., Brightwell, R. Kyorku & Williams, B. (1990) Control of tsetse fly (Diptera: Glossinidae) populations using traps at Nguruman, south-west Kenya. Bulletin of Entomological Research 80, 265276.CrossRefGoogle Scholar
Hargrove, J.W. (1981) Tsetse dispersal reconsidered. Journal of Animal Ecology 50, 351373.CrossRefGoogle Scholar
Hargrove, J.W. (2000) A theoretical study of the invasion of cleared areas by tsetse flies (Diptera: Glossinidae). Bulletin of Entomological Research 90, 201209.CrossRefGoogle ScholarPubMed
Hargrove, J.W. (2001) Mark-recapture and Moran curve estimates of the survival probabilities of an island population of tsetse flies Glossina morsitans morsitans (Diptera: Glossinidae). Bulletin of Entomological Research 91, 2536.CrossRefGoogle Scholar
Hargrove, J.W. (2001) The effect of climate on density-independent mortality in populations of male Glossina m. morsitans in Zimbabwe and Tanzania. Bulletin of Entomological Research 91, 7986.CrossRefGoogle Scholar
Hargrove, J.W. & Williams, B.G. (1998) Optimized simulation as an aid to modelling, with an application to the study of a population of tsetse flies, Glossina morsitans morsitans Westwood (Diptera: Glossinidae). Bulletin of Entomological Research 88, 425435.CrossRefGoogle Scholar
Hursey, B.S. & Allsopp, R. (1983) Sequential applications of low dosage aerosols from fixed-wing aircraft as a means of eradicating tsetse flies (Glossina. spp.) from rugged terrain in Zimbabwe. 31 pp. Harare, Tsetse and Trypanosomiasis Control Branch.Google Scholar
Knols, B.G.J., Willemse, L., Flint, S. & Mate, A. (1993) A trial to control the tsetse fly, Glossina morsitans centralis, with low densities of odour-baited targets in west Zambia. Medical and Veterinary Entomology 7, 161169.CrossRefGoogle ScholarPubMed
Oladunmade, M.A., Feldmann, U., Takken, W., Tenabe, S.O., Hamann, H.-J., Onah, J., Van der Vloedt, A.M.V. & Gingrich, R.E. (1990) Eradication of Glossina palpalis palpalis (Robineau-Desvoidy) (Diptera: Glossinidae) from agro-pastoral land in central Nigeria by means of the sterile insect technique. In Sterile insect technique for tsetse control and eradication. pp. 523. Vienna: IAEA.Google Scholar
Rogers, D. (1977) Study of a natural population of Glossina fuscipes fuscipes Newstead and a model of fly movement. Journal of Animal Ecology 46, 309330.CrossRefGoogle Scholar
Snedecor, G.W. & Cochran, W.G. (1980) In Statistical methods. pp Ames, Iowa, Iowa State University Press.Google Scholar
Thomson, J.W. & Wilson, A. (1992) A review of developments in tsetse fly (Glossina spp.) control by application of insecticide to cattle. Bulletin of Animal Production in Africa 40, 14.Google Scholar
Vale, G.A., Hargrove, J.W., Cockbill, G.F. & Phelps, R.J. (1986) Field trials of baits to control populations of Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae). Bulletin of Entomological Research 76, 179193.CrossRefGoogle Scholar
Vale, G.A., Lovemore, D.F., Flint, S. & Cockbill, G.F. (1988) Odour-baited targets to control tsetse flies, Glossina spp. (Diptera: Glossinidae), in Zimbabwe. Bulletin of Entomological Research 78, 3149.CrossRefGoogle Scholar
Vale, G.A., Hursey, B.S., Hargrove, J.W., Torr, S.J. & Allsopp, R. (1984) The use of small plots to study populations of tsetse (Diptera: Glossinidae). Insect Science and its Application 5, 403410.Google Scholar
Vreysen, M.J.B., Saleh, K.M., Ali, M.Y., Abdulla, A.M., Zhu, Z.-R., Juma, K.G., Dyck, V.A., Msangi, A.R., Mkonyi, P.M. & Feldmann, H.U. (2000) The use of the sterile insect technique (SIT) for the eradication of the tsetse fly Glossina austeni (Diptera: Glossinidae) on the Island of Unguja (Zanzibar). Journal of Economic Entomology 93, 123135.CrossRefGoogle Scholar
Willemse, L. (1991) A trial of odour baited targets to control Glossina morsitans centralis (Diptera: Glossinidae) in west Zambia. Bulletin of Entomological Research 81, 351357.CrossRefGoogle Scholar
Williams, B., Dransfield, R. & Brightwell, R. (1992) The control of tsetse flies in relation to fly movement and trapping efficiency. Journal of Applied Ecology 29, 163179.CrossRefGoogle Scholar