While the rest of us spent summers trying to fend off mosquitoes with swats and sprays, Todd struggled with a different problem: He couldn’t get his mosquitoes to bite.
He gallantly proffered his arm. He laid out a smorgasbord of mammals and birds. But the little-known Orthopodomyia signifera and Orthopodomyia alba, two mosquito species that breed in waterfilled tree holes, seemingly turned up their proboscises in disdain. “No one has ever gotten them to bite anything,” laments the chairman of Clark University’s biology department.
Fortunately for us, not all of the world’s 3,400 mosquito species bite people—although some warm evenings, it feels as if they do. Throughout the summer, you are likely to be visited by species whose Latin names leave no doubt as to their popularity: there is the perturbing Coquillettidia perturbans, the vexing Aedes vexans and, what some consider the worst of all, Aedes solicitans—a salt-marsh mosquito named after lawyers. It bites more during the day than most, and it won’t fly away from even vigorous shooing.
Though mosquitoes originated in the Tropics and the greatest number of species still live there, the farther north you go, the greater the number of individuals. “Our most vivid memories of bloodthirsty mosquitoes,” recalled Adrian Forsyth and Ken Myata in Tropical Nature, “come not from the Tropics but from pastoral New England woods and idyllic Rocky Mountain meadows.” Northern mosquitoes are not only more numerous but generally more annoying in every way: They buzz louder, they land harder, they itch more. Blame this annoyance on lack of monkeys, suggest the authors. For millennia, tropical mosquitoes have had to adopt sneak attacks and soft landings to avoid the dexterous hands of monkeys, kinkajous, and coatimundis. “Northern biters exhibit no subtlety in their approach, because no hand or paw will rise to crush them,” they write.
By the time you get to the Arctic, things are even worse. Tundra pools hatch hordes of mosquitoes that literally blacken the sky. Canadian researchers have reported a rate of nine thousand bites per minute—sufficient to exsanguinate a scientist completely in two hours.
Oddly, though, for much of its life, any given individual mosquito would make a perfectly fine companion. As larvae, they live harmlessly in water, and they spend most of their adult lives sipping nectar from flowers, pollinating many species. The males never bite. When it comes time to lay eggs, all females bite something, but not necessarily you. Some species of mosquitoes drink only the blood of lizards. Others specialize in birds. No one has figured out what Orthopodomyia signifera or Orthopodomyia alba like. Livdahl finally gave up in frustration.
Because of their role as disease vectors, mosquitoes are widely studied. Thousands of entomologists and other scientists around the world are presently trying to raise mosquitoes in their laboratories. Not all readily breed in captivity—rather like pandas in zoos. But happily, some twenty years ago, science worked out a way to remove mosquitoes’ sexual inhibitions: anesthetize the female, and cut off the male’s head; touch their abdomens together, and presto! everything works by reflex. (Incidentally, decapitation doesn’t seem to bother many insects. In fact, removing the head from the bloodsucking Rhodnius bug of South America increases its life span more than tenfold.)
Generally, mosquitoes are easy to work with in the lab. Some scientists actually grow fond of them. John D. Edman, an entomologist at the University of Massachusetts at Amherst, is sympathetic to their plight. Most mosquitoes that drink human blood would probably prefer something else, he says. Human blood, he notes, is low in isoleucine, an amino acid that female mosquitoes need to build their egg proteins. But we have slaughtered and crowded out so many other species that for many mosquitoes, we are all that’s left on the menu. “What’s a poor mosquito to do,” Edman asks, “but go for the naked ape with the second-rate blood?”
If we were fewer and less destructive, mosquitoes might not be such a bother to us. But we’re not, and they are. Mosquitoes kill more humans than any other animal on Earth: one million people die of mosquito-borne malaria each year. Mosquitoes also transmit more than a hundred viral diseases, not to mention a host of parasitic diseases causing blindness, deformity and excruciating pain.
The worst part about mosquitoes is not that they bite but that they drool. Viruses, bacteria, and parasites are spread via the mosquito’s saliva, which it injects beneath your skin in copious amounts. It contains an anticoagulant, without which every meal would clot in its throat and the insect would need the Heimlich maneuver. Proteins in the saliva elicit the itchy welt you get after a mosquito bite, although some people eventually become immune.
Bruce Landers, superintendent of mosquito control of Suffolk County in Massachusetts, says that the welt might be smaller if you let the mosquito finish its meal; ostensibly, it will suck up most of its own saliva with the last sip of your blood. Plus, if you can stand it, a feeding mosquito is rather interesting to watch.
The mosquito’s proboscis looks like a straw, but actually, it is a top and bottom lip, four sets of cutters and a saliva-injecting syringe, all so thin and long that the whole shebang can be inserted into the skin. Then the cutters saw back and forth through the tissue, slicing small blood vessels open. An undisturbed mosquito will thrust and withdraw her mouthparts five to ten times before locating enough blood for a full meal. Often, she will insert the proboscis bent back toward her body, and then she will have to stand on only her rear legs to feed so that the proboscis can straighten out. If you let her feed till full, her abdomen, filled with four times her own weight in blood, will look like a red Christmas tree light, and she’ll fly away logy.
What is the best way to get rid of mosquitoes? One solution: more mosquitoes. Anopheles barberi is our friend. Unlike most other mosquito larvae, which are filter-feeders, this one is predatory and preys on newly hatched larvae of other mosquitoes. One young A. barberi can eat up to a hundred other mosquito larvae per day, and better yet, Todd Livdahl notes affectionately, “They go on slaughter rampages.” Under certain circumstances, they will, weasel-like, kill more than they can eat. Unfortunately, these shy mosquitoes are rare, hatching only in dark, rotten tree holes.
One thing that does not work against mosquitoes, says mosquito-control expert Landers, is lighted electrified traps. “They tend to draw more mosquitoes into the vicinity of the light,” he explains. His advice: “Give it to your neighbor.”