The mosquito is the most dangerous animal in the world, at least as far as humans are concerned. It carries diseases that kill more than one million people a year (Bates). Assuming that humans had the ability to wipe out all mosquitoes everywhere, should we?
The first step in understanding this issue is to explain if and how we would do it. To begin, there are around 3,500 species of mosquito and most of those don’t bother humans at all, living entirely off of plant and fruit nectar. Only 6% of mosquito species drink blood from humans, and of that 6%, only the females use blood to develop their eggs. Finally, of these species, only about half are vectors for human diseases. So most of us can probably agree that not all mosquitoes need to be wiped out (Bates).
“Because tampering with ecosystems is so tricky, it is important not to use methods that are too broad” (Shelomi). For this reason, any sort of pesticides and/or poisons are out. They would most likely have many undesirable side effects in addition to not being viable globally. One possible option is the “Sterile Insect Technique” or “SIT” for short. In the 1950’s it was used to eradicate screw-worms from the US and Mexico, saving the US cattle industry alone over $20 billion. The process involves exposing the males in a lab to X-Rays and later Gama Rays in order to sterilize them before releasing them into the wider population. This technique has been tried with mosquitoes in the past; however, unfortunately, the males exposed to the radiation are unable to effectively compete with other males and normal reproduction continues (Shelomi).
Another technique has been developed by entomologist Luke Alphey and his team is called “RIDL”, which stands for “Release of Insects carrying Dominant Lethals”. This technique involves genetically modifying large groups of insects with a gene that disrupts the normal system of cellular reproduction. This group in the lab is then given a type of antibiotic to allow them to survive to sexual maturity before being released into the wild. Any offspring of that original group will quickly die due to the inability for their cells to reproduce (Shelomi).
In Brazil, a biotech firm by the name of Oxitec used this technique to modify large groups of mosquitoes with the RIDL gene. In 2009 about three million of the modified mosquitoes were released in a site on the Cayman Islands and by 2010, Oxitec recorded a 96% decrease in local mosquito populations (Bates). This method is fairly effective locally; however, mosquitoes have been observed to quickly repopulate the area. This means that the researchers need to constantly maintain the population through repeated RIDL releases.
In 2012 a UC Berkeley lab led by Jennifer Doudna developed a revolutionary new technique for editing DNA. They observed a set of special enzymes found in certain bacteria that allowed the organism to edit its own DNA in order to fight off viruses. These two enzymes are called CRISPR and Cas9. Jennifer Doudna and her team were able to replicate this process in the lab, allowing them to easily edit any strain of DNA they targeted. Later the following year, a separate team led by MIT bioengineer Feng Zhang and Harvard’s George Church showed that it could work on living cells. This discovery opens up almost limitless possibilities for genetic manipulation (Adler).
So then this brings us back to the question of whether or not we should try to eliminate mosquitoes. To start out, there is no way to possibly quantify millions of human lives. However, that doesn’t mean we should be so quick to wipe out mosquitoes altogether.
As stated earlier, most of us can probably agree that not all mosquitoes need to be eradicated, seeing as most of them are harmless pollinators. The few species that do spread disease kill over one million people annually. So, assuming we could entirely eliminate those mosquitoes responsible, we would save millions of human lives. The world already struggles with overpopulation, and you might argue that eliminating our last real “predator” would be fairly irresponsible. Another argument is from a moral standpoint. In the BBC news article by Clair Bates, the author argues that there would be “some who say it would be utterly unacceptable to deliberately wipe out a species that is a danger to humans when it is humans that are a danger to so many species”. If we eliminate mosquitoes to save ourselves, how many more species might we destroy? Not to mention the fact that in saving so many people, present and future, we might very well be accelerating our own destruction.
If we approach the issue from a utilitarian standpoint we could argue that by killing mosquitoes we would be endangering thousands of other species and possibly even causing unforeseen problems for ourselves down the road. By killing off mosquitoes we would simply be making a judgment that human lives are of greater value than that of other species. CRISPR has been around for a while but people aren’t exactly jumping to save antelope by eradicating lions. Finally, in terms of population dynamics, a huge boom in antelope populations, without control by predators, wouldn’t necessarily benefit antelope as a species.
Another commonly made argument is that removing a species from the ecosystem can have many unintended effects further down the line. Mosquitoes are an important food source for many organisms such as birds and bats, and their larvae are consumed by fish. They are also an important pollinator for many species of plants. However, the niche of those few species of mosquitoes would most likely be filled by other insects and even other species of mosquito (Bates).
Although the removal of those mosquitoes could very well have some unintended side effects down the line, the global ecosystems would most likely not suffer too substantial of a blow; at least not in terms of their place in the food chain. However, the mosquito also serves a much less obvious role that many people tend to overlook. The presence of mosquitoes has substantially limited the expansion of humans in many places with delicately balanced ecosystems like tropical rainforests and much of Africa and Asia.
For places like this, a substantial increase in population and tourism would mean almost certain destruction of ecosystems that have remained relatively untouched for thousands of years. As quoted in the BBC News magazine, science writer David Quammen argued that “mosquitoes have limited the destructive impact of humanity on nature”.
If the threat of these insects and their diseases disappeared one can easily see how places like the Congo and parts of Uganda would quickly be developed into major tourist destinations. Time and time again we have seen places be ruined by tourism and other industries like logging and agriculture. Small amounts of tourism can be beneficial but it can be a double-edged blade. An increase in people can quickly start to irreversibly damage an area.
In coastal Thailand, a combination of industry and tourism in recent years has turned many of its once vibrant reefs into vast barren wastelands of grey rubble completely devoid of fish life. Another example is the famous North American Redwood forests. Even in the United States, tourism has severely damaged much of the park. The tremendous amount of foot traffic has caused the soil to compact, crushing the roots of many ancient trees and has been slowly killing these great titans (CBS).
An even larger concern is over the use of CRISPR Cas-9 itself. Once we start modifying natural species to our own whim we could very well be opening up pandora’s box. “Do we want to live in nature, or in Disneyland” (Adler). Another fear is that through the wider use of CRISPR we could be putting new immensely powerful weapons into the wrong hands. Normally we could breed any kind of animal we want but natural selection would most likely “wipe the floor with them”. However, once you start talking about things like CRISPR, you have to assume that whatever you’re making will spread once it gets outside the lab (Adler).
The fact that on any one person could choose to permanently alter the natural order of the world with the flick of a switch should probably scare you. Every time we choose to use gene drive technology like CRISPR there is a chance we make a mistake. Any alteration someone decides to make very well may not be able to be undone: “Human error will win out, if not deliberate human action” (Adler).
One modern day example of this is the intentional introduction of species. The natural environment has developed a delicate balance over millions of years, and so when new species are introduced in the wild, or in this case GMO species, it can have many unintended side effects. For example, in Australia, large numbers of Cane toads were introduced in the hopes that they would help to control populations of Cane beetles. Almost immediately the cane toads spread throughout Australia unchallenged due to the lack of predators. Back in their native home, other animals had evolved to consume cane toads. However, in Australia, they have no natural predators. The cane toads, as opposed to the general consensus, failed to control cane beetle populations, instead, feeding off of other small amphibians and reptiles as well as spreading disease (Wikipedia). In retrospect, introducing cane toads was obviously a mistake. Genetically modified species are similar in many ways. Anything you introduce may very well not have its own natural niche. This means it may have little competition or predation to limit its spread.
Most scientists agree, now that CRISPR has been created, it’s less a question of whether or not it will be used, but more a question of how and by whom. I have little doubt that CRISPR will be used to create genetically modified crops and livestock or even to cure certain human diseases. However, that’s not to say we shouldn’t proceed with extreme caution.
In the end, what the issue really boils down to is whether or not we should eradicate diseases like Malaria, Dengue, Zika, and Yellow Fever. The mosquitos are really just a vector for the disease. The majority of people seem to have no issue swatting a mosquito, so the question isn’t really whether or not we should kill mosquitoes but more if we should “kill” the virus. People have suggested many creative solutions to eliminate the viruses without harming the mosquitoes, but we are still left with the same problems of human overpopulation and destruction of natural habitats. I’m not sure we can justify playing God in order to save ourselves as humans when we know we could be dooming hundreds of other species.
Adler, Jerry. “Kill all the Mosquitoes?!” Smithsonian, 16 Jun. 2017
www.smithsonianmag.com/innovation/kill-all-mosquitos-180959069/. Accessed 10 Mar. 2019
Bates, Clair. “Would it be wrong to eradicate mosquitoes?” BBC News, 28 Jan. 2016.
www.bbc.com/news/magazine-35408835. Accessed 10 Mar. 2019
CBS, News. “Trying to protect California redwoods from too much love” CBS, 18 Dec. 2017.
.Accessed 17 Mar. 2019
Shelomi, Matan. “What Would Happen If We Eliminated The World’s Mosquitoes?” Forbes, 13 Sep. 2017.
www.forbes.com/sites/quora/2017/09/13/what-would-happen-if-we- eliminated-the-worlds-mosquitoes/#518b817511f6. Accessed 10 Mar. 2019
Wikipedia. “Cane toads in Australia” Various Authors, 21 Mar. 2019
http://www.wikipedia.org/wiki/Cane_toads_in_Australia. Accessed 23 Mar. 2019