Browsing by Author "Ng'habi, Kija Richard"

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    Environmental predictors of mating competitiveness in male anopheles gambiae sensu stricto (DIPTERA: CULICIDAE) mosquitoes
    (Unversity of Dar es Salaam, 2007) Ng'habi, Kija Richard
    The enhancement of mating competitiveness of released males carrying the malaria refractory gene to be introduced among wild populations of females of Anopheles gambiae mosquitoes, is critical to malaria-vector control programmes. Current evidence suggests that genetically engineered males have low mating fitness. As a means to compensate for this reduced fitness, this study was undertaken in an effort to identify environmental conditions that maximize their mating competitiveness and optimise laboratory-rearing regimes.Anopheles gambiae first instar larvae were subjected to three different crowding treatments in the first experiment and three treatments in each experiment were competed against each other for access to females to assess their mating competitiveness. Their long-term survival and teneral energetic reserves were assessed. The low-crowding treatment males were 11 times more competitive than males from high crowding and 3 times more than males from medium crowding treatment. The medium nutritional level males were 6 times more competitive than males from the high nutritional level and 2 times more than those from low nutritional level. Long-term survival and energetic reserves did not influence mating competitiveness. Body size influenced the overall probability of males to secure female mates, but mating competitiveness was dictated by phenotypic similarity of males to the available females. Therefore, releasing males that are phenotypicaly close/similar to the abundant females in the wild would maximize the mating lications of the results to the new vector competitiveness of released males. The implication of the results to the new vector control approaches is discussed.