AUTOGENY IN DIVERSE POPULATIONS OF AEDES-AEGYPTI FROM EAST-AFRICA

  • 1 January 1977
    • journal article
    • research article
    • Vol. 28  (1) , 77-82
Abstract
Autogeny in A. aegypti was found in many diverse populations throughout the range of East Africa. Degree of autogeny may be measured either by a relative method using an autogeny index (AIx), or by direct count of eggs in dissected ovaries and expressed in percentage. Degree of autogeny varied from population to population but it was always higher in the dark feral A. a. formosus than in the domestic A. a. aegypti form. The highest degree of autogeny occurred in the dark A. a. formosus form from Uganda, where in some populations it was as high as 34%. Some autogenous females have a tendency to retain fully developed eggs in their ovaries up to 4 wk for later oviposition. At the beginning of oogenesis, the autogenous females deposit yolk granules in many follicles. As soon as the follicles reach the resting stage, translocation of yolk from many to few follicles takes place. The number of eggs developed autogenously depends on the level of nutritional reserves carried by the females from the larval stage. Autogeny could possibly serve as one of the preservation mechanisms of hematophagous species when hosts are not available. The vector capacity of autogenous populations of A. aegypti for transmission of pathogens is substantially lower than anautogenous ones because of their nonhematophagous feeding behavior at the 1st gonotrophic cycle and shorter survival of females.

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