Long Live the Mosquito: Cautioning Against Deliberate Extinctions

@bitfairy recently wrote an article that was featured on steemSTEM Distilled advocating the extinction of mosquitoes. And, indeed, there are some good reasons to take the idea seriously. Malaria is the most notable reason- this mosquito-carried disease kills nearly half a million people every year. Other diseases carried by mosquitoes, including West Nile, Yellow Fever, Zika, tularemia, and more, infect nearly 700 million people a year, killing over a million of them total. It's all nasty stuff. Thanks to it, mosquitoes kill more humans than any other animal by a long shot. And yet I'm still somewhat opposed to wiping out mosquitoes.

*A female Culiseta longiareolata mosquito. Female mosquitoes are the only ones who suck blood. * [Image source]

At the very least, we need to make an exception for the mosquitoes that don't suck human blood. Of the 3,500 mosquito species, only 100 suck human blood. Of those hundred, only around 30-40 are known to transmit disease. Even though it'd be nice not to have mosquitoes around at all, convenience is hardly a good excuse to threaten ecosystems- and threaten it they would. Mosquitoes are a key part of many ecosystems, like the Arctic, where they make up a huge amount of the biomass. Many Arctic birds are dependent on mosquitoes for food, and their loss would likely cause a population crash. As if that weren't enough, much of the Arctic ecosystem is affected by the migration of caribou herds, which frequently change direction so as to face into the wind when traveling, which helps them avoid mosquitoes. Eliminating this threat would massively change the caribou herd directions, altering the environment massively.

That being said... most of the worst diseases are tropical, so if we just avoid wiping out any Arctic species, problem solved, right? Well, maybe. It's a lot harder to determine the ecological importance of mosquitoes in the more complex ecosystems of the tropics. There tend to be a lot more alternative insect food sources in these regions, but it's questionable whether their predators could easily adapt. As weird as it sounds, some animals are so well adapted to particular prey that they have difficulty capturing anything else- or even attempting to. Aquatic ecosystems are especially vulnerable to mosquito loss- mosquito larvae tend to be one of the primary food sources found within them.

A female mosquitofish. These tiny freshwater fish eat disproportionately large numbers of mosquito larvae to their size, and are useful in suppressing mosquito populations. Unfortunately, they tend to be highly invasive, and often wipe out local species through aggression and out-competition. Deciding whether to introduce them into a region is a tricky question- they can sometimes be highly effective at controlling mosquito-borne disease, but other times can be ineffective and not worth the environmental cost. [Image source]

It's still an open question about how critical mosquitoes are to non-Arctic ecosystems, however. As prominent of an ecologist as E.O. Wilson as said that we could wipe mosquitoes out without any sort of environmental catastrophe occurring. But, frankly, this is pretty hubristic. We are nowhere near close to having the ability to predict the environmental consequences of nearly any species' extinction, let alone one that makes up as much global biomass as mosquitoes.

The methods used to drive mosquitoes extinct are also critical. In the past, humans have wiped out local populations of mosquitoes by draining or filling the wetlands where they breed. This, however, was nigh-universally environmentally catastrophic. Wetlands are basically the single most important land-based ecosystem, both in biodiversity and their positive effects on the regions around them, such as shielding vulnerable coasts from storm surges or sequestering. huge amounts of atmospheric carbon. There are, however, more targeted strategies, like introducing sterile males into the population or genetically engineering species to produce more males than females.

The Plasmodium parasite, the cause of malaria. The strange lifecycle of this protozoan is responsible for the virulence and resilience of malaria. [Image source]

What about the human consequences of wiping out mosquitoes? If you read my post on Avengers: Infinity War, you might remember me talking about Malthusian crises. One fear that might come up is that wiping out disease-carrying mosquitoes might cause the population to grow much more rapidly in these regions, resulting in even worse problems than they have today. However, it turns out that lowered child mortality rates actually go hand in hand with lowered birth rates, so eliminating malaria and other mosquito-borne diseases would likely slow population growth leading to overpopulation issues. Given that malaria and other mosquito-borne diseases are often claimed to be a major cause of many of the social and economic problems of the third world, well... we can't simply dismiss the arguments for extinction. It's a big deal. It also should be noted, however, that we've reduced deaths via malaria by 60% over the last few decades- it's not like extinction is the only option.

There are fairly convincing arguments on both sides. I'm not going to come out and simply claim that we should or should not wipe out disease-carrying mosquitoes. (Though I am going to flat out say we shouldn't eliminate non-disease carrying mosquitoes and Arctic mosquitoes. That would be moronic.) We've certainly wiped out plenty of species before, often deliberately, so we're definitely capable of doing it. I am, however, going to advocate extreme caution here. Believing that we understand the consequences of an action this severe yet is hubristic in the extreme. Scientific knowledge is far from as advanced as we like to think it is at times. We haven't even touched on the moral aspect of deliberately wiping out another species yet, either- though, when it comes to mosquitoes, we're certainly on safer moral ground.

Also, I'm really, really happy I live in a place with basically no mosquitoes.

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Bibliography:

• https://io9.gizmodo.com/what-if-every-mosquito-on-earth-went-extinct-tomorrow-1646840383
• https://io9.gizmodo.com/ask-an-entomologist-anything-you-want-about-mosquitoes-1646596878
• https://www.nature.com/news/2010/100721/full/466432a.html
• https://www.ajol.info/index.php/eamj/article/view/9179
• https://rockstarresearch.com/engineering-the-extinction-of-40-species-of-mosquitoes/
• https://en.wikipedia.org/wiki/Plasmodium
• https://en.wikipedia.org/wiki/Mosquito-borne_disease
• https://en.wikipedia.org/wiki/Mosquito
• https://en.wikipedia.org/wiki/Mosquitofish
• https://en.wikipedia.org/wiki/Malaria
• https://news.vice.com/article/heres-why-its-a-very-bad-idea-to-wipe-mosquitoes-off-the-face-of-the-earth
• https://www.pri.org/stories/2016-04-04/why-famous-biologist-wants-eradicate-killer-mosquitoes
• https://www.nature.com/news/2010/100721/full/466432a.html
• https://www.theguardian.com/global/2016/feb/10/should-we-wipe-mosquitoes-off-the-face-of-the-earth