Late one April afternoon two surf casters wet their lines in the Gulf of Mexico, off Cape Sable, Fla. They fished for sharks and between them caught five blacktips, all more than six feet long. As twilight descended, salt-marsh mosquitoes arrived in force. Every few minutes their numbers seemed to increase exponentially, like one of the 10 plagues visited on the house of Egypt. The fishermen retreated to their tent and, except to pee, stayed inside drinking beer and listening to sharks cut the surface. At 2 a.m., in his haste to get outside before his bladder burst, one man broke the zipper on the tent, which allowed inside a Biblical cloud of mosquitoes. Then, in a Florida rendition of the cliff scene in Butch Cassidy and the Sundance Kid, the two men ran into the Gulf of Mexico and kept company with the accommodating sharks till sunrise. At that point only their lips were showing.
The two fishermen who told me their story at least had each other for commiseration. Everglades National Park rangers tell of a lone fisherman whose skiff broke down in nearby Whitewater Bay. He spent the night submerged, breathing through a straw.
The late Dr. George Craig, a Notre Dame biology professor who was considered the preeminent authority on mosquitoes, once estimated that it would require 1,120,000 bites from the pesky critters to drain all the blood from an adult human. Craig never said where to test his supposition nor which of the world's approximately 3,500 species of mosquitoes would be up to the task of exsanguinating a human. One of his former graduate students, George O'Meara, however, had an idea.
O'Meara, a professor of entomology at the University of Florida's Medical Entomology Laboratory in Vero Beach, is one of a team of scientists at the laboratory whose careers hover around mosquitoes. He opts for the town of Flamingo, on Cape Sable in Everglades National Park. At the height of the rainy season—July through September—shallow pools in the mangrove forest alternately flood and dry. If the cycles happen to be spaced five or six days apart, two species of salt-marsh mosquitoes, Aedes taeniorhynchus and A. sollicitans, proliferate in astronomical numbers. Their eggs, laid on damp ground, mature in five days,
O'Meara has conducted research in Flamingo for 25 years, and every year he must apply to the national park for a permit to collect mosquitoes. Laughing, he says, "You don't need a permit to slap them." If the parking lot is empty of visitors when he arrives and the ranger's white car is black with insects, O'Meara is thrilled, for he knows that the mosquito population must be intense.
Here is a story to place Flamingo's insect life in the proper perspective. One summer in the early days of Everglades National Park (established in 1947), a pesticide fogging truck had to spray five times a day to make Flamingo tolerable for the few summer staff members who lived there. Driven to distraction by the biting insects, rangers called park headquarters near Homestead, a comfortable 38 miles away, and asked permission to pull back. Apparently, that summer mosquitoes near Homestead—there are at least 40 species in the park—were tolerable, and headquarters denied the request, suggesting that the rangers were sissies. To make the point, one Flamingo ranger followed the fogging truck and filled a large grocery bag with mosquito carcasses. He sent the bag back to headquarters. The next day a message reached Flamingo: Pull back.
Fixed to the bulletin board in the Flamingo Ranger Station is THE FLAMINGO MOSQUITO METER, which reports to park visitors what the day's amplitude of biting insects is. The meter features a picture of a large, nasty-looking mosquito whose proboscis points to one of five categories: enjoyable, bearable, unpleasant, horrible, hysterical. Next door, a gift shop sells a popular bumper sticker that looks like a cross between ads for an exterminator and for the Red Cross. It reads, I GAVE AT FLAMINGO.
Salt-marsh mosquitoes are not selective feeders; they're opportunists. Several years ago I watched a cloud of them engorge in the nostrils and around the eyes of an eight-foot-long crocodile, which basked in the sun, seemingly oblivious to the intrusion. When loggerhead sea turtles crawl out of the Gulf of Mexico to nest in the bone-colored sand of Cape Sable, every turtle sports an entourage of mosquitoes. Outside O'Meara's office is a flight cage in which he and other biologists have tested the response of various species to hungry salt-marsh mosquitoes. Birds that rely on stealth or camouflage to capture food—barred owls, green-backed herons, black-crowned night herons and great blue herons, for instance—wait like stones, rarely flinching, while clouds of mosquitoes ply their trade. Active feeders such as white ibis and snowy egrets twitch and bite, often eating the bugs that try to bite them.
The walk-in flight cage is built like a large wood-framed screen porch. Some years ago, O'Meara enlarged his study population to include two officials of the Accutronics Corporation, which at the time marketed an antimosquito device called the Mosquito Hawk. The company claimed that the Mosquito Hawk mimicked the noise made by the beating wings of a dragonfly, a major mosquito predator, and thus kept mosquitoes at bay. The inventor agreed to a test in the cage. To prepare for it, O'Meara starved several thousand female salt-marsh mosquitoes (only females suck blood; males sip plant juices). The inventor of the Mosquito Hawk entered the flight cage, four buzzing black boxes fixed to his belt. The mosquitoes began to feed, undeterred by the high-pitched sound. Within seconds the man turned to flee, but the door had jammed. Panic reigned until O'Meara rescued him.
O'Meara has been bitten by salt-marsh mosquitoes so many times in the course of his research that he has become immune to their bites—no slapping, no itching, no swelling. Inhaling mosquitoes, however, can still cause discomfort. A hungry female mosquito, which needs a high-protein meal of blood to produce a clutch of eggs, is attracted to carbon dioxide and lactic acid, both of which are given off by respiring and active birds and mammals. She also may key in on an animal's profile and on dark-colored clothing, like the olive-green uniforms worn by rangers in Everglades National Park. Drinking ginseng tea or eating bananas, vitamin B, garlic, brewer's yeast or Mrs. Paul's Fish Sticks—all suggested as can't-miss home repellents—fails to keep mosquitoes away. Commercial bug repellents may keep mosquitoes from biting, but they contain DEET, the active ingredient in most repellents, which is absorbed by the skin and has been linked to seizures and deaths. It also dissolves plastic and vinyl, which renders binoculars and cameras permanently sticky. Although acquired immunity may be reliable and safe—the Zen approach to living with mosquitoes—who would want to get bitten the requisite several thousand times each year for many years to become desensitized?