As the number of bacteria in mosquitoes’ guts (x axis) went up,
the malaria parasite levels dropped faster than a cartoon anvil.

What’s the News: We know the bacteria living in our guts are important to our health—but the bacteria in mosquitoes’ guts could be too. Researchers have discovered a species of mosquito gut bacteria that destroys the malaria parasite, keeping the disease from spreading to humans. This explains why some Anopheles mosquitoes (the only genus that transmits malaria) don’t spread it, and it spurs the imagination towards possible ways of tamping down the disease.

How the Heck:

Scientists have long wondered why some Anopheles mosquitoes don’t seem to carry malaria, while others of the same species or strain do. Mosquitoes’ immune response to the malaria parasite, Plasmodium, and their gut bacteria were known to play a part in this, but to uncover exactly what was going on, scientists collected gut bacteria from wild mosquitoes and watched what they did to the parasite in Petri dishes.
They identified one bacterium in particular that severely impaired the parasite’s development. When they fed it to mosquitoes, parasite levels plummeted (see graph above).
To find out how the bacteria were doing it, ...