Notes on the Ecology of a Natural Glossina austeni (Diptera: Glossinidae) Population in the Jozani Forest, Unguja Island of Zanzibar

Abstract

Studies were made of Glossina austeni captured with sticky panels during the dry and wet season in the northern and central part of the Jozani forest on the island of Unguja, Zanzibar. The density of the fly population was significantly higher in the northern part of the forest than in the central. Female and male daily catches remained stable in time in the northern part of the forest but the density of the male fly population declined significantly in the central part of the forest at the end of the dry season. The magnitude of the catch and the sex ratio of the samples was highly affected by the trap site in both locations. Only samples in the central part of the forest were biased towards one of the sexes depending on the seasons. The age composition of the male flies was independent of locality and season but the one of female flies was influenced by the seasons in the central part of the forest. The breeding and abortion rate of flies were similar in the two locations both during the wet and dry seasons. The stability of the fly population in terms of density and composition is probably a reflection of the optimal environmental conditions in this primary forest habitat.Resume-Des etudes ont ete effectuees sur Glossina austeni capture avec des panneaux gluants pendant la saison seche et la saison des pluies dans la partie nord et centrale de la foret Jozani sur l'ile d'Unguja, Zanzibar. La densite de la population des mouches tsetse etait plus elevee d'une maniere significative dans la partie nord de la foret par rapport a la partie centrale. Les captures quotidiennes des males et femelles restaient stable dans le temps dans la partie nord de la foret, mais la densite de la population male diminuait d'une maniere significative dans la partie centrale de la foret a la fin de la saison seche. L'endroit du piege, aussi bien au nord que dans la partie centrale, influait beaucoup sur la grandeur de la capture et la proportion des femelles dans les echantillons. Seuls les echantillons dans la partie centrale de la foret penchaient vers une majorite d'un des sexes dependant des saisons. La composition d'age des mouches males ne dependait pas de l'endroit ou de la saison, mais dans la partie centrale, les saisons influaient sur la composition d'age des mouches femelles. Le taux de reproduction et d'avortement etaient comparables dans les deux endroits aussi bien pendant la saison des pluies que pendant la saison seche. La stabilite de la population des mouches en termes de densite et de composition est probablement le reflet de conditions optimales de l'environnement dans cet habitat de foret primaire.

Evaluation and improvement of sticky traps as monitoring tools for Glossina austeni and G. brevipalpis (Diptera: Glossinidae) in north-eastern KwaZulu-Natal, South Africa

“…Sticky traps of various design and colour combinations have been shown to be useful for the monitoring of G. austeni on Unguja Island, Zanzibar, throughout a tsetse control/ eradication trial (Vreysen et al, 1999a(Vreysen et al, , b, 2000aSaleh et al, 2001;) and other population ecology studies (Vreysen & Khamis, 1999). These traps were also used to survey G. brevipalpis on Mafia Island, Republic of Tanzania (Msangi et al, 2001).…”