What if humans could become invisible to mosquitoes? Scientists at the University of California, Santa Barbara, recently experimented with altering the vision of Aedes aegypti mosquitoes, which appear during the day. (A different species comes out at night.) Aedes aegypti rely on dark visual cues to hunt, so researchers used gene editing to eliminate two of the mosquito’s light-sensing receptors. This didn’t blind the insects altogether, but it made it difficult for them to see humans. The discovery could save lives, as the mosquitoes spread viruses such as yellow fever and Zika to millions of people each year. Some experts worry that altering genes could lead to unexpected environmental consequences, but others see it as a way to manage the population without harmful pesticides. That’s important as climate change makes it easier for the insects to invade new areas of the planet. “The better we understand how they sense the human,” says researcher Yinpeng Zhan, “the better we can control the mosquito in an eco-friendly manner.”