Fitness advantages in multiple blood-feeding: the Aedes aegypti example

Abstract

Only a few of the over three thousand species of mosquitoes in the world have evolved a close association with human settlements (i.e. domestic habits) and a subsequent heavy reliance on humans as their primary blood source. These include the most important vectors of human parasitic diseases, i.e., malaria, dengue and filariasis. Representatives of all three major mosquito genera have made this transition from wild to domestic environments, so this association seems to have evolved independently on several occasions due to similar environmental circumstances. Mosquito feeding preferences are not well understood in terms of either neurobehaviour or genetics but would appear, superficially at least, to be a good target for genetic transformation, i.e., turning human-feeding species into species that seldom feed on humans or transmit their diseases. Understanding how domestic species arose and the current fitness advantages for maintaining those behavioural traits is critical for assessing the potential for manipulating and reversing this process. Aedes aegypti, perhaps the most domesticated of all mosquito species, is used as the prime example in exploring these issues