Ecologist Eben Paxton, speaking on a cell phone from somewhere in one of Hawaii’s forests, wanted to talk about the scary events happening on the island of Kauai.
The “bird crash,” he calls it.
Hawaii’s fourth-largest island, says Paxton, a scientist with the U.S. Geological Survey, is seeing a sudden, rapid decline in native birds.
The prime suspect is avian malaria. It’s being spread by mosquitoes and it kills rare birds such as the 'i'iwi, a bright red honeycreeper with a curvy Dr. Seuss beak. Surveys carried out on the island’s rugged, roadless interior are finding fewer birds than ever before. Extinction for some species looks imminent.
So now a group of government officials, conservationists, and scientists in Hawaii are seriously looking at a high-tech solution: genetically modified mosquitoes.
They say the modified bugs, whose offspring die quickly, thereby reducing mosquito populations, could be the best chance to save Hawaii’s endangered birds. If these discussions move forward, one idea would be to release millions of genetically modified bugs to drive mosquitoes off of Kauai’s plateau and maybe right out of the entire archipelago.
The discussions around the first “landscape scale” use of gene-modified insects are still at an early stage and have been coӧrdinated by the U.S. Fish and Wildlife Service, which is responsible for endangered species. A spokesman at the agency’s Honolulu office declined to confirm the agency’s role, but said it was looking at “several” recovery plans for forest birds.
What’s certain is that genetically modified organisms are political dynamite on Hawaii. Some districts have passed ordinances to ban biotech crops from being planted. No one knows how Hawaiians would react to GM mosquitoes, but lately, mosquito technology has been winning positive attention as a potential high-tech fix for human diseases such as Zika. One company, Oxitec, is testing GM mosquitoes in Brazil and hopes to do so in Florida. Because of a genetic addition to their DNA, those bugs have offspring that die prematurely. Release enough of them and the number of mosquitoes can drop drastically, although they don’t disappear altogether.
While fighting human disease gets the attention and the funding, conservation could end up being just as important a use of advanced biotechnology. At the San Diego Zoo, there are plans to save the northern white rhinoceros by cloning animals from frozen tissues. Scientists have created a genetically modified American chestnut tree resistant to the blight that’s mostly wiped them out.
Separated by 2,500 miles from the nearest land, the Hawaiian archipelago has a diversity of species even greater than Darwin’s famous Galapagos Islands. But these organisms developed in such isolation that they weren’t adapted to the threats brought by Western explorers and immigrants. These days, Hawaii is called the extinction capital of the world—434 species of plants and animals are listed as endangered by the United States. And more than half the native forest birds are already extinct.
Hawaii had no mosquitoes up until 1826. That’s when, historians say, a whaling vessel that had taken on water in Mexico carelessly “drained dregs alive with wrigglers” into a stream on Maui. Soon avian malaria followed. By 1902, travelers reported a person could spend hours in the forest and “not hear the note of a single native bird.”
In fact, some birds had retreated to higher ground. Above 4,000 feet, it’s too cold for Culex quinquefasciatus, the southern house mosquito, the one that gives malaria to birds. But these refuges are now under threat due to a warmer and wetter climate.
The situation is tragic. And a little bit fascinating. Because islands are isolated ecosystems, they’re also a good testing ground for new conservation tactics. That’s what has mosquito experts studying the Hawaiian bird situation closely. One of them, Luke Alphey, is the scientist who developed Oxitec’s mosquitoes and who now heads a group studying insect and spider genetics at the Pirbright Institute, in the U.K.
Alphey says he has a student working on modifying the culex species of mosquitoes troubling Hawaii’s birds and thinks the technology would probably work, even on such difficult terrain as Hawaii’s volcanic mountains. A couple of years ago, he wowed desperate ecologists with the idea when he visited Hawaii. “People loved it. This was the first time anyone had proposed anything that could change the whole discussion,” says Dennis LaPointe, a mosquito scientist at the U.S. Geological Survey. “It got people thinking that molecular techniques are the way to go.”
A decade ago, the U.S. Fish and Wildlife service said it would cost $2.5 billion over 30 years to preserve honeycreepers and other forest birds, including by buying land and restoring habitats. But GM mosquitoes could be a much cheaper way to give the birds more time. “It seems to me it could be done economically,” says Alphey. “It would cost a lot less than $3 billion, that’s certain.”
The most urgent situation is on Kauai, a smaller island without a big mountain to offer the refuge of high elevations. In a prelude to extinction, wildlife officials are capturing pairs of honeycreepers in order to keep them in captivity.
No one has ever applied GM mosquitoes to such a vast landscape. Mosquitoes are too fragile to be tossed out of planes; some people have floated the idea of using drones. “A lot of these mosquito techniques have been applied to pretty small areas, but we are taking about thousands of square kilometers of rain forest,” says Michael D. Samuel, a wildlife ecologist at the University of Wisconsin-Madison who has built computer models of the extinction threat facing Hawaiian birds due to climate change. “To me getting rid of wildlife disease over such a big area is hard. That said, the perfect place to experiment with these technologies is on an island. We know a lot about what’s driving the system and we can make predictions.”
Paxton says he is rooting for an all-out effort against the mosquitoes. He says people hope to see conventional sprays followed up with Oxitec-style bugs to drive down mosquito numbers and give the birds a respite from malaria. Eventually, in a few years, a newer technology called a gene drive, also in development as a fix for human malaria in Africa, might be used to eliminate mosquitoes from the islands altogether. With that approach, mosquitoes are modified to spread a gene when they reproduce that eventually kills them all.
“It would be nice to get rid of the mosquitoes,” says Paxton. “Hawaii used to be a true bird paradise.”