Breakthrough or breaking the ecosystem?

Scientists consider eradicating mosquitoes

Scientists are calling it a breakthrough: they are considering using genetically modified mosquitoes to drive a mosquito species into extinction in the Florida Keys. Sound like something out of a Marvel comic book? Many citizens think so, and are raising concerns about the practice, mainly that wiping a species out could have ecological backlash that we have not— indeed, can not— consider. Meet OX513A, a genetically modified strain of the Aedes aegypti mosquito. Floridians are already familiar with the natural aedes aegypti. It is recognizable by white stripes on its legs and body. This is the common Floridian mosquito, as far as Florida natives are concerned: however, the species is quite invasive. Aedes aegypti originated in Africa and spread with trade to Europe, Southeast Asia, and the Americas. While the species is most prevalent in the Southeast United States in North America, a very alarmed article from 2013 reports that the species has spread all the way to California. For years, Floridians have struggled to combat these tiny predators, which not only suck blood from their hosts, but can also carry a host of diseases from dengue to chikungunya and yellow fever. An army of pesticides have been used in succession to combat the growing population of parasites, but even a very effective pesticide cannot kill every mosquito and the offspring of any survivors will likely be immune to the chemical: in fact, six chemicals exist to kill the mosquitoes, but they have already evolved to be immune to four of them. OX513A seeks to circumvent that altogether. The mosquitoes are genetically altered to carry birth defects. How? Oxitec, a British biotech firm developed the strain of mosquito by giving it a dominant genetic birth defect that it passes on to its children, which— thanks to the defect— die before reaching maturity. Only the males are released in this practice: males mate with wild females and give their offspring the defects. Males are non-biting, which could allow residents to rest easier, knowing that they won’t be bitten by genetically-altered mosquitoes. Females are manually removed from the population before they are released: however, it is unnervingly possible that technicians can— and in past studies have— missed a female or two. Oxitec performed a 2012 experiment in the Cayman Islands where they received some backlash about overlooked females. Critics accuse them of not properly informing the residents that they could be bitten by a stray, genetically-altered female. However the results are encouraging: no reports of bites occurred, and a 96 percent reduction in mosquito population was reported, though it can and should be argued that not enough time has passed to determine if there are any adverse side effects to the area’s finely balanced ecology or to humans. However, this is not new science. Oxitec developed the bugs over a decade ago and has been arguing with the federal government to release them in the Keys for five years. They partnered with the Florida Keys Mosquito Control District to try to pursue this course of action. It is only recently that the Federal Department of Agriculture seems willing to entertain the notion. Residents have been polled: 60 percent of them are “OK with the trials” according to NPR. 10 percent to 20 percent are opposed. However, city and district meetings show stronger opposition. Despite the many diseases that Aedes aegypti carry, those diseases are rare. According to USA Today, Marilyn Smith, a Key West resident, was one of the most eloquent opposers. “She says neither disease has had a major outbreak yet in Florida, so ‘why are we being used as the experiment, the guinea pigs, just to see what happens?’” USA Today writes. Mosquito Control District personnel have a different outlook: they want to prevent an outbreak, and find themselves getting farther and farther behind as the mosquitoes adapt. As for environmental and ecological impact, a single study explores the consequences of the widespread eradication of mosquitoes. The entire article can be read here: To summarize: the consequences could easily be mitigated by other species filling their space in the ecosystem, however no other species could perform Aedes aegypti’s role exactly as they do. Other species would be forced to adapt (and quickly) and we have some idea of what that would look like, but not entirely. North Floridians have their own concerns, though Oxitec assures that they are ill-founded. Could the genetically altered OX513A spread up to North Florida? Says Oxitec: a resounding “no.” The genetically altered ones are not capable of producing surviving offspring. They only survive a single generation which lasts only 4-6 weeks: hardly long enough for their tiny wings to carry them to Monticello. And even if they hitched a ride in an unsuspecting tourist’s car, they would not live long enough to affect local populations. If the practice is accepted, however, the OX513A could be coming to a backyard near you.

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