Delayed mating in the malaria vector Anopheles funestus compared to Anopheles arabiensis (Diptera: Culicidae).

Abstract

Mating is a vital behavior for mosquito reproduction, yet it remains poorly understood under captive conditions. We examined the copulation dynamics of 2 key malaria vectors, Anopheles funestus sensu stricto Giles and Anopheles arabiensis Patton, under laboratory settings in Tanzania. We conducted observations in 24-h cycles and monitored copulation events and insemination of females, initially using flashlights for nighttime visibility, followed by red lights in subsequent experiments. We observed how variations in mosquito age and artificial lighting influenced mating success for these 2 mosquito species within cages under controlled conditions. We found that An. arabiensis copulated relatively soon after emergence, with 32.4% of individuals mating by day 3 postemergence, whereas An. funestus showed delayed activity, reaching a similar mating frequency by day 8. The introduction of artificial red light significantly accelerated copulation in An. funestus but did not affect An. arabiensis. Sperm transfer and mating plug delivery in over 92% of copulating pairs of both species was confirmed by dissection. Mating occurred primarily at night, with distinct peaks at 10 PM for An. arabiensis and 11 PM for An. funestus. In conclusion, our findings revealed species-specific differences in reproductive behavior, which could improve the colonization of An. funestus, a species historically challenging to rear in captivity. These insights also may facilitate the development of new vector control technologies, such as sterile insect techniques and genetic-based approaches, that exploit mosquito mating behavior.