The effect of rainstorms on adult Anopheles funestus behavior and survival.

We describe the effect that the passage of a cold front, with a subsequent heavy rainstorm ten days later, had on a population of Anopheles funestus mosquitoes collected exiting houses or in light-traps from a village in southern Mozambique. Temperature effects explained 40% (r=0.634; p <0.001) of the variation in numbers of males collected and 19% of the variation in gravid females collected (r=0.437; p=0.033). The age structure of mosquitoes varied according to distance from the breeding site (χ(2) = 64.1, df 6, p <0.001). The proportion of parous insects that were caught in the light-traps with sacs (χ(2) = 6.33, d.f. 2, p=0.042) and young insects that had mated before being collected (χ(2) = 13,3, d.f. 2, p=0.001) were reduced on the night of the rain but this effect was short lived. It is concluded that the effect of rain on mosquito populations depends on the kind of water body used for larval development.