For the Sake of Science

Whenever I find myself under attack by mosquitoes, I will tend to remark to another person how much I would enjoy a mosquito genocide. Sure, a midge and/or horsefly genocide would be lovely as well – not to mention a whole host of other insect holocausts – but it’s the mosquito I really hate. I mean hate. I would eat raw onions and celery for the rest of my life if I could do away with the little bastards.

The natural response I get from people when I express my desire for mosquito eradication is, “Wouldn’t that really mess up the food chain?” I respond, half-jokingly, that I’m willing to make that sacrifice. Of course, along with most other people, I have always believed that the death of all mosquitoes, or at least the ones that bite humans, would have long-reaching ecological ramifications. And, again, along with most other people, I naturally don’t want to see that happen. But as it turns out, maybe it wouldn’t be such a bad thing after all:

Most mosquito-eating birds would probably switch to other insects that, post-mosquitoes, might emerge in large numbers to take their place. Other insectivores might not miss them at all: bats feed mostly on moths, and less than 2% of their gut content is mosquitoes. “If you’re expending energy,” says medical entomologist Janet McAllister of the Centers for Disease Control and Prevention in Fort Collins, Colorado, “are you going to eat the 22-ounce filet-mignon moth or the 6-ounce hamburger mosquito?”

With many options on the menu, it seems that most insect-eaters would not go hungry in a mosquito-free world. There is not enough evidence of ecosystem disruption here to give the eradicators pause for thought.

At this point in the evolution of life, any significant hole left open by one species will quickly be filled by another. Even when the world has seen mass extinctions, life has been quick to fill in the gaps. And that’s with broad gaps. The loss of mosquitoes would be a very narrow niche to cover.

But there are other mosquito-reliant organisms. The question, however, is, how reliant are they? Mosquitoes make up a lot of the biomass in both aquatic and summer arctic environments. In aquatic environments it’s their larvae that contribute to the ecosystem, bringing about greater variation in other organisms while also producing nutrients for plants. In the arctic, they are food for migratory birds. But in both cases other organisms could easily take their place. Though mosquitoes have co-evolved with so many other species, so have so many other insects and microorganisms. They aren’t unique except in their high level of annoyance.

Attempts at Genocide

When the French attempted to build a canal in Panama, one of their major setbacks was disease carried by mosquitoes. It wasn’t until shortly after they started construction that it was even known that mosquitoes were vectors for diseases such as malaria and dengue fever. And even then, it wouldn’t be for some time – about when the French gave up – that it was known just how much mosquitoes could spread disease.

Enter the Americans.

When the U.S. set to construct the canal, measures were taken to drastically cut down on the mosquito population in the area. Standing pools and ponds of water were drained near construction and living areas. High grasses were cut down to create fields mosquitoes were less likely to cross. Oils were added to difficult to drain ponds. Acids and caustic sodas were even spread in great quantity. And what effect did this have on the ecology of the surrounding area? Apparently none. (At least none as a result of the loss of the mosquito.) Of course, this wasn’t an eradication, and it didn’t impact all areas, but it was a massive effort and the mosquito population was reduced significantly.

So could we do something like that, but for all mosquitoes, in all areas? Probably not. Many places in the South have programs where standing buckets of water and other common mosquito breeding grounds are destroyed. Other places spread sprays which kill mosquito larvae. These methods help, but they aren’t enough to fix the problem. And in all likelihood, there are no practical methods available that could bring about the Great Mosquito Genocide. Really, I trust that if humans could get rid of this pest, we would have long, long, long ago.

But don’t let our inability to destroy these little bastards take anything away from the dream of mass mosquito murder:

“They don’t occupy an unassailable niche in the environment,” says entomologist Joe Conlon, of the American Mosquito Control Association in Jacksonville, Florida. “If we eradicated them tomorrow, the ecosystems where they are active will hiccup and then get on with life. Something better or worse would take over.”

Filed under: Evolution, Science | Tagged: Janet McAllister, Joe Conlon, Mosquito, What would happen if mosquitos were killed | 3 Comments »