Search

Anthropophilic mosquitoes such as Aedes aegypti L. (Diptera: Culicidae) have been shown to have superior reproductive success on human blood when sugar is not available. Life-table experiments were conducted with Aedes albopictus Skuse and Ae. aegypti to compare the effects of sugar availability on age-specific survivorship, lifetime and daily fecundity, and blood-feeding frequency when offered human blood daily. There were no significant interactions between the effects of sugar availability and mosquito species for these four variables, indicating similar effects of sugar availability for both species. Lifetime fecundity was not significantly affected by sugar availability, but sugar-deprived females had significantly reduced age-specific survivorship than did sugar-fed females. In absence of sugar, females took bloodmeals twice as often, resulting in a higher daily fecundity. The results indicate that superior reproductive success on human blood without sugar does not seem to be limited to highly anthropophilic mosquito species, such as Ae. aegypti. We conclude that evolution of a highly anthropophilic feeding strategy is not an inevitable result of the ability to thrive on human blood alone. [ABSTRACT FROM AUTHOR]

As a result of numerous successful invasions by both Aedes albopictus (Skuse) and Ades aegypti (L.), the current worldwide distributions of these mosquito species overlap. Shared larval habitats and shifts in the distribution and abundance of resident A. albopictus or A. aegypti after the establishment of the other species suggest that competitive displacement occurs. Experiments on larval competition between North American populations of the two species showed that A. albopictus has the competitive advantage under local field conditions, which apparently accounts for displacement of A. aegypti from much of the United States after the invasion of A. albopictus. The role of competition, and potential shifts of competitive advantage in different parts of their worldwide ranges are unknown, but variation due to intraspecific or environmental differences is possible. In the current study, we measured the performance of larvae of Brazilian populations of A. albopictus and A. aegypti competing under field conditions in Rio de Janeiro, Brazil. Finite rates of increase for each species were estimated and the effects of species composition, larval density, and leaf litter resource levels were determined. A. albopictus maintained positive population growth at higher combined densities and lower per capita resource availability than did A. aegypti. A. albopictus showed higher survivorship than A. aegypti under all treatments and leaf litter resource levels. These results indicate that in Brazil, just as in North America, A. albopictus is a superior larval competitor to A. aegypti when exploiting leaf litter resources. Our results further suggest that this competitive advantage for A. albopictus is likely to be independent of mosquito population origin, local environmental conditions, and local differences in the types of leaves that form the resource base of the aquatic habitats of larvae. [ABSTRACT FROM AUTHOR]