It’s easy to just think of malaria as a medical problem. It is caused by single-celled parasites—Plasmodium—that are spread through the bites of other parasites—mosquitoes. To beat the disease, we need to neutralise either Plasmodium or its mosquito carriers, using drugs, insecticides, nets, or even genetically-modified competitors.

But malaria is also an ecological problem. Mosquitoes aren’t static, unchanging targets. They move around. They mate. They breed in some areas and not in others. Their populations swell and contract throughout the year. They bite at varying times of day. We need to understand these subtle quirks of mosquito life, because they all have a huge impact on our strategies for fighting malaria.

Consider the Sahel—a belt of land that stretches across Africa’s waist,