Interspecific mating between Aedes aegypti and Aedes albopictus and its contribution to population declines of Aedes aegypti

The yellow fever mosquito, Aedes aegypti, and the Asian tiger mosquito, Aedes albopictus, are vectors of important arboviruses, including dengue. They originated, respectively, in Africa and Asia and have extended widely their native ranges due to their invasive characteristics. In the last three decades, A. albopictus has spread broadly and has established in new continents. Invasions by A. albopictus have been associated with some abrupt declines of A. aegypti. Mating interference has been proposed as a possible mechanism for such declines, based on the detection of interspecific mating in nature and the discovery that injected accessory gland extracts from A. albopictus males induced mating refractoriness in virgin A. aegypti females. However, how this sterilization process takes place, remains unresolved.

Mating was achieved by exposing virgin female A. aegypti to males of A. albopictus followed by blood feeding, and exposure of these females to males of the same species. Eggs were collected from each female and hatched, as a means of determining whether a female had been rendered refractory to mating. After interspecific matings, A. aegypti females were unable to mate with males of their own species and lay viable eggs. Currently, we are labeling male A. albopictus with stable isotopes, to determine if female A. aegypti may receive male accessory gland substances during interspecific matings, even if sperm are not transferred to the spermathecae.

This research is helping to clarify how A. albopictus males may nullify the reproductive potential of A. aegypti females and thereby contribute to population declines of the yellow fever mosquito.