Interaction ofWolbachiaand Bloodmeal Type in Artificially InfectedAedes albopictus(Diptera: Culicidae)

Abstract

Maternally inherited Wolbachia bacteria are being introduced into vector mosquito populations, with the goal of reducing the transmission of diseases such as dengue fever. The infection dynamics of Wolbachia depends upon the ability of Wolbachia to manipulate host reproduction as well as any fitness costs imposed upon the host. Some vector mosquito species are opportunistic blood feeders, utilizing both human and nonhuman vertebrate hosts, and the effects of bloodmeal source on Wolbachia phenotype is not well understood. Here we transfer wMelPop Wolbachia from Drosophila melanogaster (Meigen) into wild-type Aedes albopictus (Skuse) and characterize the resulting triple infection by examining for an effect of human and mouse blood on the Wolbachia infection persistence and phenotypes. When provided with human blood, the triple Wolbachia infection was persistent, with high maternal inheritance and relatively little fecundity cost, and a pattern of imperfect unidirectional cytoplasmic incompatibility was observed in mating experiments between wild-type and triply infected individuals. With mouse blood, reduced female fecundity and low maternal inheritance were observed in wMelPop-infected females, which affected the typical pattern of unidirectional CI. Our findings indicate the interactive effects of Wolbachia infection and blood source drive distinct shifts in the Wolbachia-host symbiotic association.

An elusive endosymbiont: DoesWolbachiaoccur naturally inAedes aegypti?

“…Most of these infections induce cytoplasmic incompatibility, and many also reduce the ability of their hosts to transmit viruses, making them desirable for field release. For mosquito species that are naturally Wolbachia-infected such as A. albopictus, novel infections can be generated either by first removing the natural infections with antibiotics (Calvitti, Moretti, Lampazzi, Bellini, & Dobson, 2010;Suh, Mercer, Fu, & Dobson, 2009) or by introducing the novel infection into an infected mosquito, resulting in a superinfection (Suh, Fu, Mercer, & Dobson, 2016;Zhang, Zheng, Xi, Bourtzis, & Gilles, 2015). Different novel Wolbachia infections may be incompatible with each other (Ant, Herd, Geoghegan, Hoffmann, & Sinkins, 2018) and the addition of Wolbachia strains to create superinfections can lead to unidirectional incompatibility, where females of the superinfected strain produce viable offspring following matings with males with any infection type, but superinfected males induce cytoplasmic incompatibility when mated with singly infected and uninfected females (Joubert et al, 2016).…”

An elusive endosymbiont: DoesWolbachiaoccur naturally inAedes aegypti?

“…For mosquito species that are naturally Wolbachia-infected such as Ae. albopictus, novel infections can be generated either by first removing the natural infections with antibiotics (Suh et al, 2009, Calvitti et al, 2010 or by introducing the novel infection into an infected mosquito, resulting in a superinfection (Zhang et al, 2015, Suh et al, 2016. Different novel Wolbachia infections may be incompatible with each other (Ant et al, 2018) and the addition of Wolbachia strains to create superinfections can lead to unidirectional incompatibility, where females of the superinfected strain produce viable offspring following matings with males with any infection type, but superinfected males induce cytoplasmic incompatibility when mated with singly infected and uninfected females (Joubert et al, 2016).…”

Effects of alternative blood sources on Wolbachia infected Aedes aegypti females within and across generations

“…While many mosquito species utilise a wide variety of blood sources to facilitate the egg laying process, Ae. aegypti appears dependent on human blood for this purpose [24,34]. Both groups fed on non-human blood showed a significant decrease in egg hatch rates compared to mosquitoes fed on human blood, regardless of their Wolbachia infection.…”

“…However, issues relating to insufficient storage time [20] or reduced egg hatch rates [23] are reasons why alternative blood sources continue to be used in different locations. Where these are used, they may affect the success of releases by (1) directly decreasing the fitness of released mosquitoes, if feeding produces sub-optimal offspring that cannot compete effectively with wild mosquitoes, (2) promoting a process of genetic adaptation to non-human blood that has negative fitness consequences for released mosquitoes when feeding on human blood again, and (3) reducing Wolbachia-related effects like maternal transmission, CI and viral blockage [24].…”