Effect of larval nutrition on reproductive success in males of the African malaria mosquito (Anopheles gambiae)

The success of genetically modified mosquitoes for malaria control depends on manipulation of the factors that enhances their reproductive success within wild populations. We studied the effect of three levels of larval food on development time, adult body size, emergence, insemination and oviposition success, survival and average life expectancy of male Anopheles gambiae s.l. mosquitoes. We used three food levels: high (200 mg), medium (100 mg) and low (50 mg) amounts of Tetrafin Godfish food. Larvae were reared in plastic trays with larval density of 200 individuals per tray. After emergence, 10 females were mated with 20 males (per food level) in three separate plastic bucket cages for one hour. Females were subsequently dissected after death and mating confirmed by examining the spermathecae. Survival and average life expectancy experiments were conducted for two groups of unmated males: Starved (water only) and Fed (10% sugar solution). Mean adult male body size was significantly influenced and correlated with larval nutrition. Oviposition success was significantly correlated with insemination success but not with male larval nutrition. Survival and mean life expectancy experiments showed significant variation in the distribution of survival trends, with males fed the high food amount having the lowest survival. Although adult male body size and survival/mean life expectancy were significantly influenced by larval nutrition, other components of male reproductive success were not. This work points to a need to understand the effect of quantity and quality of different larval food sources on the reproductive success of transgenic mosquitoes.