Impact of life-shortening Wolbachia infection on immature competitiveness in Aedes aegypti

Endosymbiont bacteria Wolbachia affect host fitness in various ways. An example is the manipulation of host reproduction by Wolbachia induced cytoplasmic incompatibility (CI), which increases the relative fitness of infected adults, promoting the spread of infection into an uninfected population. The reproductive advantage afforded by Wolbachia has been suggested as a way to drive desirable phenotypes into natural populations to reduce transmission of insect vectored diseases. Life-shortening Wolbachia (wMelPop, popcorn) has previously been shown to induce complete CI in uninfected females mated with infected males of the dengue virus vector Aedes aegypti. Although the fitness advantage due to CI in the adult reproduction of infected individuals may alone have the potential to invade and replace the uninfected population, it is also crucial to understand the effect of popcorn Wolbachia on other life stages such as larvae. We examine cohort larvae competing within and between strains (infected and uninfected) at two different larval densities. The results demonstrate significantly reduced competitiveness in infected larvae with decreased survival and increased development time particularly when competitive effects were high. The results are discussed within the context of using popcorn Wolbachia infections to reduce transmission of the dengue virus by Ae. aegypti.