Scientists create killer moth to control pests

James Meek / Guardian UK 5mar01

Scientists are preparing to start trials of the world's first genetically modified insect, an unnatural born killer moth that will fly over cotton fields, passing a deadly gene on to its pestilent kin as an alternative to pesticide.

Although the GM moth will be released in Arizona, the technology used to create the killer gene has been developed by a British team led by Luke Alphey, of Oxford University. The scientists believe that the chances of the killer gene spreading beyond the species it is intended to harm, the pink bollworm, is very small, and would do no harm if it did.

But the US department of agriculture still has to give consent for the first part of the trial, which would involve a tightly controlled release of moths with another gene inserted to track any possible cross-species transfer.

Scientists need to target the bollworm larvae, which feed on cotton plants, before developing into moths. The idea is to take insect eggs in the lab and insert into their DNA a gene from a fruit fly which would normally damage their metabolism so badly that they would die.

In the lab, however, the larvae survive, because they are dosed with an antidote to the effects of the killer gene. They will grow into adult moths, which are naturally immune to the effects of the gene, and will then be released over the cotton fields in huge numbers.

Unaware that by mating they are both creating and assassinating the next generation, the GM moths will mate with wild moths and each other. The female moths will lay their eggs as normal. But their offspring will have inherited the killer gene. In the wild, the larvae will find no antidote and will die.

In the initial trial, which could take place next year, 3,600 moths will be given a jellyfish gene that glows under special light instead of the killer gene. This will show what happens to GM insects when they encounter their wild counterparts and other species.