In Defense of the Mosquito: 10 Things to Know About Summer’s Biggest Annoyance
Mosquito image via Shutterstock
Between the itching and the welts and the fears of West Nile, it's easy to forget that mosquitoes are a wonder of evolution, and maybe they don't really get a fair shake from us. Of over 3,000 known species, only 80 actually bite people, and at least one eats other mosquitoes for us. They grow from egg to adult in just five days, begin mating within minutes of hatching, and possess, by way of their stinging mouthparts, some of the coolest appendages in the animal kingdom. While I swat at them as much as the next guy, I think maybe it's time we sit down and give skeeters a little credit for all the wonderful weirdness they’ve got going on.
1. They’re excellent bad weather flyers
The average raindrop is 50 times heavier than the average mosquito, yet they buzz around in the rain with no problems. If a Boeing 747 got whacked with a similarly scaled up raindrop, there’d be 2,375 tons of water coming down on it, and things probably wouldn’t turn out as well as they do for the mosquito. How do they do it?
A common urban legend said that the bugs were nimble enough to dodge the drops. Last year, a team of engineers from the Georgia Institute of Technology watched real mosquitoes and styrofoam dummy mosquitoes with a high-speed camera during a rainy flight to see if that’s what was really happening. They found that the bugs don’t fly fast enough to dodge the drops, but their slowness is what keeps them from getting knocked out of the sky. A mosquito’s low mass even at slow speed doesn’t provide enough of a target for a raindrop to splash on collision. Instead, the drop just deforms, and doesn’t transfer enough momentum to the mosquito to disrupt its flight.
2. They’ve got a big family, and lots of relatives down south
Over 3,000 species of mosquitoes have been described around the world. At least 150 of those are found in the United States, and 85 of those call Texas home, which makes the Lone Star State the mosquito capital of the USA.
3. Some of them are really dangerous...
The female mosquito, which is the one that stings and sucks blood, is an incredible transmitter of disease and, because of that, the deadliest animal in the world. Each year, the malaria they transmit kills 2 million to 3 million people and infects another 200 million or more. They also spread other pathogens like yellow fever, dengue fever, Rift Valley fever, Chikungunya virus and West Nile virus.
4. ...and some of them aren't
Not every species of mosquito sucks blood from people, and among those that do, not every one transmits disease. Even the blood suckers don’t need to bite you for every meal. Males live entirely off of nectar and other plant fluids, and the females’ diet is mostly plant-based, too. Most of the time, they only go after people when they’re ready to reproduce, because blood contains lipids, proteins and nutrients needed for the production of eggs.
5. They’re more useful than you’d think
When you’re rubbing calamine lotion all over yourself, mosquitoes might not seem to serve any purpose but to annoy you, but many species play important ecological roles. The mosquitoes Aedes impiger and Aedes nigripes, which gather in thick clouds in Arctic Russia and Canada, are an important food source for migrating birds. Farther south, birds, insects, spiders, salamanders, lizards, frogs and fish also eat different mosquito species regularly. Plants need them, too, and some, like the blunt-leaved orchid and endangered monkeyface orchid, rely on mosquitoes as their primary pollinator.
Some mosquito species are also excellent at mosquito control. Species of the genus Toxorhynchites feed on the larvae and immature stages of other mosquitoes and will sometimes even cannibalize members of their own species.
6. They’re amazing hunters
Mosquitoes are adept at picking up on the chemicals given off by their human hosts. They can detect the carbon dioxide in our breath, the 1-octen-3-ol in our breath and sweat, and other organic substances we produce with the 70+ types of odor and chemical receptors in their antennae. These receptors can pick up traces of chemicals from hundreds of feet away, and once the mosquito closes in, it tracks its meal chemically and also visually - and they’re fond of people wearing dark colors.
7. They can be picky
If it seems like you’re always covered head to toe by bites while people who were sitting right next to you only have one or two, it’s not just paranoia; the skeeters actually are out to get you. Some people happen to give off more of the odors and compounds that mosquitoes find simply irresistible, while others emit less of those and more of the compounds that make them unattractive to mosquitoes - either by acting as repellents or by masking the compounds that mosquitoes would find attractive.
8. They have a heck of a kisser…
A mosquito doesn’t simply sink its proboscis into your skin and start sucking. What you see sticking out of a mosquito’s face is the labium, which sheaths the mouthparts that really do all the work. The labium bends back when a mosquito bites, allowing these other parts to pass through its tip and do their thing. The sharp, pointed mandibles and maxillae, which both come in pairs, are used to pierce the skin, and the hollow hypopharynx and the labrum are used to deliver saliva and draw blood, respectively.
9. …and some cool chemicals, too
The saliva that gets pumped out from the hypopharynx during a bite is necessary to get around our blood’s tendency to clot. It contains a grab bag of chemicals that suppress vascular constriction, blood clotting and platelet aggregation, keeping our blood from clogging up the mosquitos' labrum and ruining their meal.
10. They can go out with a bang
Blood pressure makes a mosquito's meal easier by helping to fill its stomach faster, but urban legend says it can also lead to their doom. Story goes, you can flex a muscle close to the bite site or stretch your skin taut so the mosquito can’t pull out its proboscis and your blood pressure will fill the bug until it bursts. The consensus among entomologists seems to be that this is bunk (you can see one guy try and fail here), but there is a more complicated way of blowing the bugs up. To make a blood bomb, you’ve got to sever the mosquito’s ventral nerve cord, which transmits information about satiety. When it's cut, the cord can’t tell the mosquito’s brain that its stomach is full, so it’ll keep feeding until it reaches critical mass. At least one researcher found that mosquitoes clueless about how full they were would keep sucking even after their guts had exploded, sending showers of blood spilling out of their blown out back end.