Many of the pests that eat our farm crops have been sprayed with pesticides so much they have evolved resistance and can’t be killed by them, just like some bacteria have evolved to become resistant to antibiotics.
But scientists at UC San Diego can now genetically engineer new insects of the same species that are not resistant to pesticides. And they can easily pass on their traits when they breed with pesticide-resistant bugs.
They’ve done it with fruit flies and say the same can be done with beetles, moths and other pests.
“So if you can make the insects sensitive to it again, then you can just keep on using the same pesticides we already have that work, but at much lower frequency and much lower doses,” said Ethan Bier, professor of biology at UC San Diego. “So the total burden you put on the environment could go down by orders of magnitude, potentially.”
The bugs, engineered in a lab, carry a genetic drive that eliminates the pesticide-resistant mutations.
Bier said the drive works quickly as the engineered insects breed with local populations. They can make a local population of bugs 100 percent pesticide vulnerable within ten generations. Bugs breed ten generations in about six months.
The genetic information that fuels the drive is designed to disappear from the insects over the same time period. That means, in the end, they become no different from the bugs we knew, prior to their exposure to insecticide.
“We’ve been able to use this genetic strategy we’ve been working on where you essentially drive a trait into a population,” Bier said.
“We’ve been able to do that in a way that the only thing that is left after you’re done is the population like it used to be. So you’ve rewilded it and there’s no genetic scar of any kind. There is no other element that is added.”
Even so, these bugs have undergone mutations in the lab and releasing them into the wild could be controversial.
With that in mind, Bier said all environmental regulations would need to be met before any of these creatures could be allowed to mate with wild populations.
The paper that describes Bier’s research appeared in Nature Communications. UCSD postdoctoral scholar Ankush Auradkar was also a co-author on the paper.
