Handout
It has been one of the most universally recognizable and aggravating sounds on Earth for 190 million years – the humming buzz of a mosquito. After a long day of hiking while camping with your family or friends, you quickly shower, settle into your lawn chair, crack an ice-cold beer and exhale a deep, contented sigh. Before you can enjoy your first satisfying swig, however, you hear that all-too-familiar sound signaling the ambitious approach of your soon-to-be tormentors.
It is nearing dusk, her favorite time to feed. Although you heard her droning arrival, she gently lands on your ankle without detection, as she usually bites close to the ground. It’s always a female, by the way. She conducts a tender, probing, 10-second reconnaissance, looking for a prime blood vessel. With her backside in the air, she steadies her cross-hairs and zeros in with six sophisticated needles. She inserts two serrated mandible cutting blades (much like an electric carving knife with two blades shifting back and forth), and saws into your skin, while two other retractors open a passage for the proboscis, a hypodermic syringe that emerges from its protective sheath. With this straw she starts to suck 3–5 milligrams of your blood, immediately excreting its water, while condensing its 20 per cent protein content. All the while, a sixth needle is pumping in saliva that contains an anticoagulant preventing your blood from clotting at the puncture site. This shortens her feeding time, lessening the likelihood that you feel her penetration and splat her across your ankle. The anticoagulant causes an allergic reaction, leaving an itchy bump as her parting gift. The mosquito bite is an intricate and innovative feeding ritual required for reproduction. She needs your blood to grow and mature her eggs.
Please don’t feel singled out, special, or view yourself as a chosen one. She bites everyone. This is just the inherent nature of the beast. There is absolutely no truth to the persistent myths that mosquitoes fancy females over males, that they prefer blondes and redheads over those with darker hair, or that the darker or more leathery your skin, the safer you are from her bite. It is true, however, that she does play favourites and feasts on some more than others.
Blood type O seems to be the vintage of choice over types A and B or their blend. People with blood type O get bitten twice as often as those with type A, with type B falling somewhere in between. Disney/ Pixar must have done their homework when portraying a tipsy mosquito ordering a “Bloody Mary, O-Positive” in the 1998 movie A Bug’s Life. Those who have higher natural levels of certain chemicals in their skin, particularly lactic acid, also seem to be more attractive. From these elements she can analyze which blood type you are. These are the same chemicals that determine an individual’s level of skin bacteria and unique body odor. While you may offend others and perhaps yourself, in this case being pungently rancid is a good thing, for it increases bacterial levels on the skin, which makes you less alluring to mosquitoes. Cleanliness is not next to godliness, except for stinky feet, which emit a bacterium (the same one that ripens and rinds certain cheeses) that is a mosquito aphrodisiac. Mosquitoes are also enticed by deodorants, perfumes, soap and other applied fragrances.
While this may seem unfair to many of you, and the reason remains a mystery, she also has an affinity for beer drinkers. Wearing bright colors is also not a wise choice, since she hunts by both sight and smell – the latter depending chiefly on the amount of carbon dioxide exhaled by the potential target. So all your thrashing and huffing and puffing only magnetizes mosquitoes and puts you at greater risk. She can smell carbon dioxide from more than 200 feet away. When you exercise, for example, you emit more carbon dioxide through both frequency of breath and output. You also sweat, releasing those appetizing chemicals, primarily lactic acid, that invite the mosquito’s attention. Lastly, your body temperature rises, which is an easily identifiable heat signature for your soon-to-be tormentor. On average, pregnant women suffer twice as many bites, as they respire 20 per cent more carbon dioxide and have a marginally elevated body temperature. As we will see, this is bad news for the mother and the fetus when it comes to infection from Zika and malaria.
Please don’t go on a shower, deodorant, and exercise strike or shelve your beloved beer and bright T-shirts just yet. Unfortunately, 85 per cent of what makes you attractive to mosquitoes is prewired in your genetic circuit board, whether that be blood type; natural chemical, bacteria, or CO2 levels; metabolism; or stink and stench. At the end of the day, she will find blood from any exposed target of opportunity.
Unlike their female counterparts, male mosquitoes do not bite. Their world revolves around two things: nectar and sex. Like other flying insects, when ready to mate, male mosquitoes assemble over a prominent feature, ranging from chimneys to antennas to trees to people. Many of us grumble and flail in frustration as that dogged cloud of bugs droning over our heads shadows us when we walk and refuses to disperse. You are not paranoid, nor are you imagining this phenomenon. Take it as a compliment. Male mosquitoes have graced you with the honor of being a “swarm marker.” Mosquito swarms have been photographed extending 1,000 feet into the air, resembling a tornado funnel cloud. With the cocksure males stubbornly assembled over your head, females will fly into their horde to find a suitable mate. While males will mate frequently in a lifetime, one dose of sperm is all the female needs to produce numerous batches of offspring. She stores the sperm and dispenses them piecemeal for each separate birthing of eggs. Her short moment of passion has provided one of the two necessary components for procreation. The only ingredient missing is your blood.
Returning to our camping scenario, you just finished your strenuous hike and proceed to the shower, where you richly lather up with soap and shampoo. After toweling off, you apply a healthy dose of body spray and deodorant before finally putting on your bright red-and-blue beachwear. It is nearing dusk, dinnertime for the Anopheles mosquito and you sit down in your lawn chair to relax with that well-deserved cold beer. You have done everything in your power to lure a famished female Anopheles mosquito (and by the way, I just moved to the seat that is farthest from you). Having just mated in a swarming frenzy of eager male suitors, she willingly takes your bait and makes off with a few drops of your blood.
She has taken a blood meal three times her own body weight, so she quickly finds the nearest vertical surface and, with the aid of gravity, continues to evacuate the water from your blood. Using this concentrated blood, she will develop her eggs over the next few days. She then deposits roughly 200 floating eggs on the surface of a small pool of water that has collected on a crushed beer can that was overlooked during cleanup as you and your party headed home. She always lays her eggs in water, although she does not need much. From a pond or stream to a minuscule collection in the bottom of an old container, used tire, or backyard toy, any will suffice. Certain types of mosquitoes desire specific types of water – fresh, salt, or brackish (a mixture) – while for others, any water will do the trick.
Our mosquito will continue to bite and lay eggs during her short life span of an average one to three weeks to an infrequent maximum longevity of five months. While she can fly up to two miles, she, like most mosquitoes, rarely ranges farther than 400 meters from her birthplace. Although it takes a few days longer in cool weather, given the high temperatures, her eggs hatch into wiggling water-bound worms (children) within two to three days. Skimming the water for food, these quickly turn into upside-down, comma-shaped tumbling caterpillars (teenagers) who breathe through two “trumpets” protruding from their water-exposed buttocks. A few days later, a protective encasement splits and healthy adult mosquitoes take to flight, with a new generation of succubus females anxious to feed on you once more. This impressive maturation to adulthood takes roughly one week.
The repetition of this life cycle has been uninterrupted on planet Earth since the first appearance of modern mosquitoes. Research suggests that mosquitoes, identical in appearance to those of today, surfaced as early as 190 million years ago. Amber, which is essentially petrified tree sap or resin, represents the crown jewels of fossilized insects, for it captures minute details such as webs, eggs, and the complete intact innards of its entombed. The two oldest fossilized mosquitoes on record are those preserved in amber from Canada and Myanmar dating from 105 to 80 million years ago. While the global environments these original bloodsuckers patrolled would be unrecognizable to us today, the mosquito remains the same.
Excerpted from The Mosquito by Timothy C. Winegard. Copyright © 2019 by Timothy C. Winegard. Published by Allen Lane, a division of Penguin Random House Canada Limited. Reproduced by arrangement with the Publisher. All rights reserved.
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