Caterpillars, unlike stubborn children, happen to enjoy eating their greens. But their love of veggies has become so extreme that they're devastating broccoli, kale and even cabbage.
To combat the vandalism of our veggies, scientists decided to tweak the genes of the caterpillars when in their adult form: moths.
Researchers from Oxitec, an extension of Oxford University, altered the genes in a species of moth called the diamondback moth (or cabbage moth). The team only altered the genes of the male moths: When these modified males mated with females, not all of their offspring lived to reproduce.
Neil Morrison, the lead researcher from Oxitec, explained to IFLScience how these moths help control the caterpillar population: "It mates with a local female moth: they have offspring, and the female offspring of that mating don't survive to reproductive age." This means that the next generation of moths has a lot fewer female moths to mate with. "So the population crashes."
This method effectively stifles a rampant caterpillar population in just a few generations. The population can be curbed in as little as eight weeks. Fortunately, the moths won't make other predators further up the food chain sick if they get eaten. "It's non-toxic, so if another predator ate the moth it would be no different to eating a regular moth," said Morrison.
The genetically modified moths aren't going to replace insecticides altogether, although "insecticide use may be reduced," commented Morrison. This has benefits for the environment: Insecticides are indiscriminate in their targets, which can have unexpected effects on ecosystems. Pests can also develop resistance to sprays, which reduces their effectiveness over time.
Spraying insecticide on broccoli. Oxitec.
This new technique isn't going to be a silver bullet for pest control. The world of agriculture is on such a large scale that it would be difficult to control with genetically modified insects alone. The bio-engineered moths are more likely to be used as a complementary pest control strategy.
The research isn't just limited to moths; Morrison added that "We're working with other agricultural pests as well: such as fruit flies and olive flies." The methods would work on pretty much any insect, though. You may recall that Oxitec have tried a similar pest control approach by genetically engineering mosquitos that only produce male offspring that survive to reproductive age. These mosquitos were released in Brazil. The motive, instead of saving crops, was to reduce the cases of dengue.