It's a pristine spring morning on the remote tip of Big Pine Key, 30 miles north of Key West. The lone paved road is surrounded by dense brush and wetlands that give way to the Gulf of Mexico. On this particular Tuesday, though, the usually silent landscape is dominated by the pulsing whoosh of a brown and tan helicopter that just touched down. Half a dozen workers in neon safety vests, surgical masks, and sunglasses emerge from the roadside and hustle toward the aircraft. Under the whirling two-blade rotor, they form an assembly line and dump bags of a yellowish substance called larvicide into cone-shaped containers on the sides of the chopper.
This is the modern frontline of the war on mosquitoes, an epic, centurieslong struggle between mankind and nature that has left an indelible mark on the Sunshine State. Minutes after landing, the helicopter is back in the air, buzzing treetops. The pilot banks a tight U-turn, cuts down to an altitude of 60 feet or so, and delivers the payload. As the helicopter bolts out of sight, a barely visible granular trail flutters toward the ground. "Don't look up," says one of the workers on the ground.
The commander in chief of this latest skirmish that's unfolding in the Keys is entomologist (insect expert) Michael Doyle, a slight, mild-mannered Midwesterner with a fastidiously trimmed salt-and-pepper mustache and rimless eyeglasses. Executive director of the Florida Keys Mosquito Control District, Doyle says that about $45,000 will be spent by the end of the day just to counter the onslaught of mosquitoes hatched in the three to four inches of rain that fell over the weekend.
Back at the agency's headquarters in Marathon, Doyle explains that the larvicide unleashed by the helicopter consists of ground-up corncobs slathered in naturally occurring bacteria that is toxic to mosquito larvae. (It would take a pickup truck-and-a-half of such larvicide to kill a human.) When the pellets land in puddles and nearby water, larvae gobble them up and die before they can morph into the flying, blood-sucking pests we so loathe.
But this method is expensive, labor-intensive, and ineffective against one of the most troublesome mosquito species, Aedes aegypti. Of the 44 species in the Keys, Aedes aegypti is the one that keeps Doyle up at night. It's the stealth bomber of mosquitoes: silent, capable of biting 20 people in a day, breeding in the shallow puddles around densely populated residential areas. Most alarming: It's the only species in the region capable of spreading dengue fever — a nasty and sometimes fatal disease that popped up in the Keys in recent years and could scare away the tourists who drive the local economy.
When Doyle left behind his days at the Centers for Disease Control and Prevention in Colorado, where he studied mosquito saliva, to take charge of the Keys in July 2011, board members who oversee the mosquito program gave him a more than $10 million annual budget, staffers with PhD's, and a fleet that includes four helicopters and two airplanes. They also gave him two orders: Cut the budget while killing more mosquitoes, and ensure that no cases of dengue fever grab headlines like they did in 2009 and 2010.
"The dengue cases were a big deal," Doyle says. "It was the first time [the disease] had been back in more than 60 years. The concern is that the Keys could be a way for dengue to get a new foothold, or a refoothold, in the United States."
Doyle's solution? To move ahead with a controversial experiment that has been in the works since before he arrived: importing and releasing millions of Aedes aegypti mosquitoes that have been genetically modified in the labs of a British biotech firm called Oxitec. These minute marvels of science are tweaked to pass down a gene that causes their progeny to self-destruct soon after hatching. Only males would be released; theoretically, they would breed with normal females and spawn offspring that keel over and die just before adulthood. The dengue-spreading population would collapse generation by generation.
If Doyle's plan goes forward, Key West will be only the fourth site ever in which these genetically modified insects have been let loose, behind Malaysia, northern Brazil, and the Cayman Islands. But not everyone is eager to tinker with Mother Nature's genetics, perhaps put off by the idea of getting bitten by a mutant mosquito. This is, after all, the Conch Republic — full of sinners, sailors, developers, and assorted rebellious characters who, in 1982, famously declared they were seceding from the United States. Here, the environment teems with beauty and biodiversity, which in turn draw legions of money-spending tourists. Local residents will fight like hell to protect their unique way of life.
Doyle understands the complexity of the situation. "We are in a weird spot, because we want to get rid of dengue and not make headlines...," he says, then adds, laughing, "Then come GM mosquitoes."