A pair of hormones work in tandem to activate or suppress mosquitoes’ cravings for blood.

The findings reveal a possible mechanism for what drives mosquitoes’ attraction to people and other animals, which has remained a mystery until now. The discovery could provide new pesticide targets for preventing mosquito reproduction and disease transmission

The females of most mosquito species — including Aedes aegypti, the carrier of the viruses that cause dengue fever, yellow fever and zika — feed on animal blood for the development of their eggs. But once they’ve eaten a blood meal, their appetite for blood shuts down until after they lay their eggs.