It’s probably safe to say that millions of people, at some point in time, have had at least passing thoughts of how to make mosquitoes extinct. These people range from backyard barbeque hosts whose parties have been marred by these uninvited guests, to people with mosquito-borne diseases such as Chikungunya or dengue fever.
Forbes published a very interesting, albeit lengthy discussion of this very possibility in their Quora section, written by Dr. Matan Shelomi, currently an assistant professor of entomology at Taiwan University. The article thoroughly breaks down the myriad environmental issues involved with the question of what would happen if mosquitoes went extinct. This would have to be a forced extinction at the hands of humans, of course, since mosquitoes have been thriving quite famously since prehistoric times. Within his discussion, Shelomi even addresses such existential questions as, “Do mosquitoes have a purpose?”
According to Shelomi, out of the over 3,000 species of mosquitoes worldwide, only a small number of them (200 or so), feed on human blood. Others feed on birds, lizards and smaller animals. Of the ones that feed on human blood, he states, many would prefer to feed on other animals. In addition, not all the human-feeding species carry human disease pathogens, and of the ones that do, not all strains are efficient vectors.
The point being made, and one that seems not only more reasonable but more conceivably attainable, is to focus on eliminating or at least reducing the mosquito vectors of human disease. The main targets here would be certain species of Anopheles, Aedes and Culex.
Shelomi goes on to discuss a number of ways scientists have or are attempting to accomplish this selective forced extinction of these disease vectors. Large-scale methods, such as massive use of pesticides, appear too risky when considering the unknown effects on other species. After all, tampering with the balance of the ecosystem has been shown in many instances to create more problems than it was intended to resolve.
One methodology used with success on screwworms in the 1950s is called Sterile Insect Technique (SIT). X-rays, and later gamma rays, were used to sterilize massive quantities of lab-reared flies, which were released into the wild to compete with for mates. In short, the technique was a tremendous success in eliminating the screwworm from the U.S., Mexico and southwards through North and Central America.
SIT apparently has demonstrated limitations for use with mosquitoes, however. Irradiation can weaken the males and/or reduce their lifespan, with the result that they are unable to attract females.
Another technology apparently being used with some success is called RIDL (Release of Insects carrying a Dominant Lethal). In this technique, the males are genetically modified to carry a lethal gene that results in their larval offspring dying before they can develop to adulthood. RIDL has resulted in massive declines of dengue vectors in the southern United States and South America. The advantages are that it has no detrimental effects on the environment or on non-target species.
As Shelomi points out, however, even with the progress of such amazing current technology, complete elimination of vector mosquito species worldwide is a long way off. In the meantime, we can work on local efforts starting in our own backyards. This goes back to taking away mosquito breeding spots by eliminating areas of standing water including poor drainage spots, piles of wet leaves and pockets of moisture found in such places as the small divots in patio furniture, potted plant trays, corners of kids’ play equipment and underneath decks.
This practicable strategy will not only reduce the number of mosquito bites we suffer, but benefit public health. It also seems to align well with the sound philosophy of thinking globally, but acting locally.
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