Wolbachia strains w Mel and w AlbB differentially affect Aedes aegypti traits related to fecundity.

Two Wolbachia strains, w Mel and w AlbB, have been transinfected into Aedes aegypti mosquitoes for population replacement with the aim of reducing dengue transmission. Epidemiological data from various endemic sites suggest a pronounced decrease in dengue transmission after implementing this strategy. In this study, we investigated the impact of the Wolbachia strains w Mel and w AlbB on Ae. aegypti fitness in a common genetic background. We found that Ae. aegypti females infected with the w Mel strain exhibited several significant differences compared with those infected with the w AlbB strain. Specifically, w Mel-infected females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the w AlbB strain. Conversely, the w AlbB strain showed only mild negative effects when compared with Wolbachia -uninfected specimens. These differential effects on Ae. aegypti fitness following infection with either w Mel or w AlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations in endemic settings. Further research is needed to better understand the underlying mechanisms responsible for these differences in fitness effects and their potential impact on the long-term efficacy of Wolbachia -based dengue control programs.IMPORTANCEThe transmission of arboviruses such as dengue, Zika, and chikungunya is on the rise globally. Among the most promising strategies to reduce arbovirus burden is the release of one out of two strains of Wolbachia -infected Aedes aegypti : w Mel and w AlbB. One critical aspect of whether this approach will succeed involves the fitness cost of either Wolbachia strains on mosquito life history traits. For instance, we found that w Mel-infected Ae. aegypti females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the w AlbB strain. Conversely, the w AlbB strain showed only mild negative effects when compared with Wolbachia -uninfected specimens. These differential effects on mosquito fitness following infection with either w Mel or w AlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations.