In Mexico, acquired herbicide resistance and insecticide genes can disrupt cotton’s ecosystem

Cotton plants native to Mexico’s Yucatan Peninsula may all look the same — unkempt and untamed bushes with flowers that shift from pale yellow to violet as pollinators visit them. But genes that have escaped from genetically modified cotton crops have made some of these native plants fundamentally different, changing their biology and the way they interact with insects.

One type of escaped gene makes wild cotton exude less nectar. With no means to attract defensive ants that protect it from plant eaters, the cotton is devoured. Another escaped gene makes the wild cotton produce excess nectar, enticing a lot of ants that might keep other insects, including pollinators, at bay, researchers report on January 21 in Scientific Reports.

“These are profoundly interesting effects,” says Norman Ellstrand, an evolutionary biologist at the University of California, Riverside. “It’s the first case that really suggests that a whole ecosystem can be disrupted” after transgenes enter a wild population.