Tuesday, November 29, 2011

Mosquitos? Kill Them All!

Eradicating any organism from this earth would have seriously bad consequences for entire ecosystems, right?

Well maybe not says Janet Fang, if the organism is the mosquito.  Writing in Nature magazine,

Malaria infects some 247 million people worldwide each year, and kills nearly one million. Mosquitoes cause a huge further medical and financial burden by spreading yellow fever, dengue fever, Japanese encephalitis, Rift Valley fever, Chikungunya virus and West Nile virus. Then there's the pest factor: they form swarms thick enough to asphyxiate caribou in Alaska and now, as their numbers reach a seasonal peak, their proboscises are plunged into human flesh across the Northern Hemisphere.

So what would happen if there were none? Would anyone or anything miss them? Nature put this question to scientists who explore aspects of mosquito biology and ecology, and unearthed some surprising answers....

...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...

...Ultimately, there seem to be few things that mosquitoes do that other organisms can't do just as well — except perhaps for one. They are lethally efficient at sucking blood from one individual and mainlining it into another, providing an ideal route for the spread of pathogenic microbes.


geonni banner said...

Well it all sounds pretty good until you get to the last sentence.

"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."

I'm wondering what the "worse" thing might be.

PBurns said...

The are a lot of types of mosquitoes, and not all are as harmful to people as others, so I am not sure we would even have to get rid of all mosquitoes to get massive benefits -- just four or five species would give us 90% of the benefit.

As a general rule, these bugs are so small and so short-lived that not too much depends on them, and so if they were eliminated nothing too noticeable would happen for the most part. My guess is we would see more Mayflies (also a small winged water-warrior insect, but not a blood sucker) and more gnats. It would not take much to fill in the void, and if we saw a 5% decline in an insectivorious bird, would we even notice? Nope. We have had far bigger dives than that NOT related to food, and no one noticed or care. The notion that if we eliminated a species the whole chain of life collapses, is simply not true. We extirpate species from areas all the time without obvious effect, and we introduce them all the time without obvious effect.


Viatecio said...

But if mosquitos went away, think of all teh monees that vets would lose by not selling overpriced heartworm medication :*(

Hey though, if that were the case, then there'd be no more moaning and groaning about "noncompliance" with HW med administration!