Over the past few months, many South Africans have wondered why there is an excessive amount of mosquitoes and flies in their homes.

Prof Johnnie Van den Berg, a professor at the North-West University’s (NWU’s) Unit for Environmental Sciences, explains where all the flies and mosquitoes are coming from.

He says the drastic increase in the numbers of these insects is due to the heavy rainfall South Africa has experienced recently.

The rise of irritating insects

According to Prof Van den Berg, mosquitoes depend on water for their survival. Female mosquitoes lay their eggs in standing water, where the larvae develop for about 10 to 20 days, depending on temperatures and environmental conditions. Adult mosquitoes then emerge from these larvae, in search of a blood meal.

He says the increased number of flies we observe is also due to the increased humidity caused by the recent rains. Fly larvae (maggots) survive on organic material such as animal dung, rotten fruit and garden refuse.

“Most of the fly larvae die during development due to desiccation and because their food sources dry out quickly. However, with the high humidity we are experiencing currently, the survival rate is much higher and explains the high number of insects we see around us,” he says.

Prof Van Den Berg says these insects will keep on increasing until winter sets in or water becomes less available.