Browsing by Author "John, Bernadette"

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    Studies on the Life History and Energy Reserves of Male Anopheles Gambiae (Diptera: culicidae) from Kilombero-Ulanga Valley
    (University of Dar es Salaam, 2007) John, Bernadette
    An attempt to develop a method for determining age and mating status of male Anopheles Gambiae, was done by observing changes in the features of their reproductive system and these observations were used to explore predictive statistical models for determining age and mating status. The features studied were spermatocysts, sperm reservoir and the clear area. It was noted that the number of spermatocysts in testes decreased with age, and the relative size of the sperm reservoir increased. The presence of a clear area around accessory glands was linked to age and mating status. Of the predictive models explored, the optimal model developed was able to categorize males into age groups of young (< 4 days) and old (>4 days) with an overall efficiency of 89%. Based on the parameters of this optimal model, a simple age predicting table was formulated. Mating history could not be reliably assessed based on this approach as virgins could not be distinguished from mated males. Furthermore the age- grading model was adopted on a comparative study of the productive potential and life-history of laboratory-reared and wild male An gambiae.s.l . three indirect indicators of male mosquito fitness: energetic reserves, body size, and survival were measured in a bid to understand the demographics and energetic limitations of these mosquitoes. The findings established that body size and lipid reserves of wild males were substantially greater than those from standard laboratory conditions. These results demonstrate that measurement of morphological features of male An gambiae.s.l reproductive system that can easily be collected in the field enables evaluation of life patterns of wild males in free-living populations.