Use pesticides on a field for long enough and the bugs that you’re supposed to be defeating will adapt. But you know what adapts faster than bugs? Bacteria. They can run through multiple generations in a day or so, and a new study shows that when bugs team up with a certain pesticide-loving bacteria, the bugs, too, can develop resistance to pesticides incredibly quickly.

This bacteria, Burkholderia, loooooves to eat fenitrothion, a hugely popular insecticide. It’s not the only bacteria that considers a round of pesticides a tasty meal, but it also happens to live in the guts of insects. Once the bacteria have settled in there, the bugs can eat the pesticide or, remarkably, have it contact their exteriors, while still coming away scot-free.

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At Ars Technia, John Timmer explains why this is a problem for pesticide users:

We’ve already known from countless examples that repeated, heavy use of a single pesticide (or drug) can help select for the evolution of resistant organisms. But generally, this selection is thought to occur over multiple generations which, for insects, tends to take a fair bit of time. Bacteria, however, can go through several generations in a day, and a single source of Burkholderia can presumably be transferred to many insects within a population.

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Basically, the bugs get insta-immunity. It’s as if, in welcoming the bacteria into their gut, they’ve found a power-up the renders them impervious to all attacks. Good for the bugs! But also one more reason to worry about the widespread use of pesticides.