Wolbachiastrain wMelM disrupts egg retention byAedes aegyptifemales prevented from ovipositing

Abstract

AbstractAedes aegyptimosquitoes are well adapted to dry climates and can retain their eggs for extended periods in the absence of suitable habitat.Wolbachiastrains transferred from other insects to mosquitoes can be released to combat dengue transmission by blocking virus replication and spreading through populations, but host fitness costs imposed byWolbachia, particularly under some environments, can impede spread. We therefore assessed the impact of twoWolbachiastrains being released for dengue control (wAlbB andwMelM) on fecundity and egg viability following extended egg retention (12 or 18 d) under laboratory conditions. Egg viability decreased to a greater extent in females carryingwMelM compared to uninfected orwAlbB females. Fertility fully recovered in uninfected females following a second blood meal after laying retained eggs, whilewMelM females experienced only partial recovery. Effects ofwMelM on egg retention were similar regardless of whether females were crossed to uninfected orwMelM males, suggesting that fitness costs were triggered byWolbachiapresence in females. The fecundity and hatch proportions of eggs ofwMelM females declined with age, regardless of whether females used stored sperm or were recently inseminated. Costs of someWolbachiastrains during egg retention may affect the invasion and persistence ofWolbachiain release sites where larval habitats are scarce and/or intermittent.