The genetic changes made to the newly released moth are much more complex, however, than those made to the bollworm—which was modified to glow for tracking and study purposes.
The moth has been genetically modified to produce offspring that will die before reaching maturity. It has a kind of genetic “kill switch.” Concerned groups like GeneWatch and the Center for Food Safety have pointed out that the kill switch is not 100 percent effective. Some GM moths survive and breed with the wild population, perhaps changing the wild population irreversibly and in unintended ways.
Feeding on crops, the diamondback moth is a pest estimated to cost farmers worldwide some $4 billion annually, says Oxitec. The hope of scientists at Cornell University, working for Oxitec, is that the GM moths will cull the population.
“It’s supposed to be an effort to reduce damage,” said Jaydee Hanson, a senior analyst at the Center for Food Safety. “But the bottom line is, they have not been transparent.”
The Center for Food Safety requested information about earlier cage trials, without success. The Cornell scientists said they were not going to release all the information to the public, that they were submitting it to peer-review first. While that information remains in the dark, 10,000 moths are to be released weekly.
Public information sessions have been cursory, Hanson said. He’s not sure even the authorities have had all the information they should have to assess the risk of the release.
“You have a bizarre situation in New York where you need a permit to release butterflies at your wedding, but you don’t need a permit to release these genetically engineered moths,” Hanson said.
Organic farming organizations worry that all the dead larvae left on the crops after the kill switch kicks in will compromise organic certification. The larvae can still chew the plants, so even if the population eventually decreases as hoped, the initial increase in population—with the release of 10,000 insects per week—could harm farmers’ fields.
GM Mosquito Experience
The GM mosquitoes released in other countries by Oxitec have a kill switch similar to that in the moth. The effectiveness of releasing these GM mosquitoes to reduce transmission of diseases like malaria has been questioned. GeneWatch published a report on Sept. 4 looking at the Oxitec mosquito releases in the Cayman Islands.While Oxitec had reported a 79 percent decrease in the mosquito population there, GeneWatch noted that a decrease only occurred in the dry season, when numbers fall anyway. GeneWatch said Oxitec studies did not show whether the population decrease continued into the wet season.
Rather than suppressing the population with its release of male GM mosquitoes, Oxitec’s own data showed spikes in the number of female mosquitoes (which can transmit disease) in the release areas. GeneWatch speculated that these spikes may be due to the unintended release of female GM mosquitoes or due to wild female mosquitoes gathering to mate with the released males.
GeneWatch and the Center for Food Safety call for greater transparency so the potential risks of releasing GM insects can be better determined before irreversible changes are made in wild insect populations.
