Could GMO fruit flies solve Australia's pest problem?

Australia is looking to control fruit flies, one of the most common pest species, through the use of biotechnology.

The Mediterranean fruit fly, or medfly, is an invasive species that is now endemic to Western Australia. The female medfly “stings” fresh fruit and then lays her eggs in the puncture site. The hatching larvae then feast on the decomposing fruit.

But a British bioengineering firm called Oxitec has created genetically modified medflies that, when released into the environment, could mate with wild fruit flies and pass on a gene that would prevent their female offspring from reaching adulthood – which would then prevent the species from reproducing and affecting more fruit crops.

The Department of Agriculture and Food in Western Australia (DAFWA) now plans to conduct an indoor trial assessment of the genetically-modified species.

"We need to evaluate new tools that could become a helpful part of integrated pest management practices," Neil Morrison, lead researcher for agricultural pest control at Oxitec, told the BBC.

Oxitec, which specializes in engineering insects for pest control purposes, has also made other insect products.

In July, the company announced that it had successfully created a genetically engineered diamondback moth with a “self-limiting gene” that would reduce its population over time. The diamondback moth is an invasive species that attacks kale, cabbage, and other crops.

"This research is opening new doors for the future of farming with pest control methods that are non-toxic and pesticide-free," Dr. Morrison told Reuters.

Genetic modification is also being employed to insects that affect humans instead of crops.

Researchers at the Imperial College London have developed an enzyme that, when applied to mosquitos, results in a genetic defect which means that over time, only male offspring are produced. When properly applied, this could effectively kill off the African mosquito Anopheles gambiae, which is thought to be a malaria vector.

However, Luke Alphey, Oxitec’s founding scientist, told the BBC that just because we now have the means to potentially eliminate Anopheles gambiae does not mean we should.

"If this species were to suffer a population crash, it's hard to see how significant negative side-effects might arise," he explained. "[But the malaria-bearing] mosquitoes are not keystone species in their ecosystems. And this technique only affects one species, Anopheles gambiae, among more than 3,000 known species of mosquitoes."  

Dr. Nikolai Windbichler, another scientist on the Imperial College research team, agreed that there were “a lot of tests to run through” before they could determine if A. gambiae would, indeed, go extinct as a result of genetic tinkering.

In the United States, scientists affiliated with the University of California recently bred a genetically-modified mosquito that completely resists becoming infected with malaria protozoans. In the study, the scientists restructured the DNA of a sample malaria-bearing mosquito from India to combat the parasite. The resulting DNA was successfully inherited by nearly 100 percent of the mosquito’s offspring, and across three generations.