It is a matter of faith with a lot of people these days—conservationists, ecologists, environmentalists and other well-informed worriers—that man is the dominant species on the planet, and that the survival of all other creatures depends on how well or how badly we behave. This judgment is based on the observation that in the last few thousand years man has subdued or exterminated many large conspicuous beasts, as well as smaller mammals, birds and reptiles. Pragmatically it has not been such a stupendous feat as we sometimes like to think. The beasts involved were never numerous or fierce enough to give us much opposition. What is often overlooked is that in really big-league biological competition, against the visible animals with whom we have been going at it hammer and tongs ever since we climbed out of the trees, we are anything but overpowering. These animals are, of course, the insects. Try telling the next cloud of mosquitoes you meet that you are the master.
No one has any idea of how many individual insects exist at any given moment, but entomologists reckon that the combined bulk of insects is considerably greater than the combined bulk of all the vertebrates. In all, there are some 800,000 known species of insects (with new ones cropping up all the time), whereas there are less than 50,000 different kinds of mammals, birds, reptiles, amphibians and fish put together. The appearance of man on the planet caused all sorts of problems and disasters for foolish, feeble beasts like the tiger, python, eagle and whooping crane, but the insects, so to speak, took us in stride. They have fattened upon us, injected plague and fever into our blood, eaten and despoiled our food, gobbled our floor joists, gnawed our winter overcoats and have, in general, unmercifully harassed our bodies and minds. The coming of man has been such a pleasant, profitable and entertaining event for insects that had we not evolved under our own steam it is quite possible they would have invented us.
Like it or not, anyone who hikes, hunts, fishes, bird-watches, photographs, golfs, picnics or otherwise pokes into the fringes of the North American boondocks is going to have to contend with our native insects, not a few of which are, in a cold, impersonal, evolutionary way, unpleasantly hostile to man. Considering the really serious, or even deadly, competition that goes on between men and insects elsewhere, the one between bugs and the people in search of outdoor recreation is a minor skirmish. But it is the kind of direct, hand-to-hand combat that serves as a showcase for bug power and which scars and embitters many of us. With no slight intended to such crawling, probing creatures as fleas, ticks and mites, perhaps the most fearsome and hated bugs which roam our land are the flying, biting, bloodsucking ones. This is the order of creatures which goes by the name of Diptera and includes, among other frights, the gnats, mosquitoes and flies.
Not that the Diptera are the most lethal of the insects commonly encountered during a vacation. That distinction goes to the Hymenoptera, an order that includes bees, wasps and hornets. The method by which a bee dispatches or temporarily incapacitates a man is fairly simple, at least from the standpoint of the bee. The stinging Hymenoptera are equipped with a small sac containing a poison that is injected into the victim along a hypodermiclike stinger. In the case of some insects, the venom can be paralyzing. So far as man is concerned, the venom is responsible for the initial pain when one is stung. For most people there are few other problems because the amount injected is very small. (In theory it would take the simultaneous stings of hundreds of bees or wasps to inject enough poison into a normal adult to cause serious illness or death.) But some individuals are acutely sensitive to Hymenoptera venom. The venom, once it enters the bloodstream, acts as an antigen, in reaction to which the body produces antibodies. The severity of this reaction is an allergic one, and varies from person to person, but those in whom it is extremely severe may enter a state of anaphylactic shock and, a few minutes after being stung, succumb because of the collapse of the vasculature. There are certain warnings, allergies being in a sense progressive afflictions. The first exposure to the antigen produces the first antibodies, and these remain in the system for as long as 40 years, to be reinforced by the antibodies produced when the person is next stung. The reaction of a person who is very sensitive to bee venom will usually be worse the second time he is stung, worse still the third time, and so on, with the possibility that somewhere along the line the results will be fatal.
The bees and their kin kill 25 or so Americans each year, and create serious medical problems for several thousand more, but the public-health statistics bearing on the matter are sketchy. Many authorities believe these figures are conservative and that an appreciable number of serious beesting cases, and even a few deaths, are either misdiagnosed or go unreported.
Among the enormous horde of insects that concern men, Hymenoptera are a fairly trivial contingent, akin to a small but cunningly equipped commando company. It is otherwise with the Diptera. Not as directly lethal as bees and wasps, they are more numerous, more widely distributed and cause infinitely more sublethal agony. If not the most dangerous, they are certainly the most aggravating and ferocious animals still abroad. Operatively, the saliva of the Diptera, which they inject into us when they bite, is an antigen like the venom of bees and capable of causing an allergic reaction. A red, hard, itchy lump is the familiar reaction most of us have to a fly bite. Some of us lump up more than others. But seldom, if ever, do we die from fly bites as we do from beestings. We just think we will.
An important difference between the stinging bees and the biting flies is what might be called motivation. Bees sting in defense of their persons or property. It is possible to remain on good terms with the Hymenoptera by avoiding offense or the appearance of offense. The flies are something else again. They are outright predators who regard us as their choice prey and hunt us down. You can be nice as pie to a horsefly, for example, and as long as he lives he is going to regard you as a meal.
There is no point in trying to escape one by running. A horsefly can keep up with the fastest horse, and the females are attracted to moving trains and automobiles, which they mistake for possible hosts. The thing the biting flies like best about us is our blood. A few flies fancy some of our other precious bodily fluids, like mucus, sweat, lymph, but these creeps are perverse rather than perilous, and there are few of them compared to the bloodsuckers. Blood is, of course, found under the skin of creatures who have it, and in order to get under our skins, and those of other mammals and birds, the flies have developed a really horrifying collection of blood-collecting instruments. Growing out of the faces of Diptera are needles, pins, punches, corkscrews, scalpels, nippers, rasps and suction tubes that make the torture instruments of the Inquisition look like Boy Scout equipment.
They are splendidly equipped to prey on us, and they do so almost everywhere. It is true that most of the Diptera require water, moist soil or vegetation in which to lay their eggs, but this is really not much of a restriction. It takes very little moisture for their purpose. A throwaway beer can half filled with water can serve as a nursery for enough mosquitoes to fill a three-man tent. There is virtually no place in the country too dry for at least some of the biting flies. Being essentially cold-blooded, most flies are inactive when the temperature goes below 50�, which gives everybody except residents of our tropical littoral some relief for at least six months out of the year. However, there is a catch even in this restriction. The bloodsucking flies are up and about at exactly the same time of the year when we feel the greatest urge to shed our clothes and disport ourselves outdoors in forest and fen. The exquisite seasonal correlation between the activities of warm-blooded creatures and that of the Diptera thirsting for their warm blood is, of course, not an accident, but an evolutionary matter. The bugs have had millions of years in which to perfect their timing.
Biting flies are bad wherever you meet them, but they are perhaps a bit badder in the north than elsewhere. The evergreen belt of our northern states on up through Canada and Alaska to the barren Arctic is wet, hot country in the summer. Bugs by the trillions are hatched out of ponds, lakes, rivers, beaver meadows, sphagnum bogs and muskeg. When the biting ones emerge they seem to be in a frenzy to get in as many licks as possible before frost comes. In great boon-docky patches of northern real estate the bugs are so ferocious that sensible creatures, such as guides, loggers, surveyors and reindeer, simply abandon the land to them, get out and do not come back until the fly season is over. Others, like moose or outdoor recreationists, who either can't get out or are so silly as to come to the fly country voluntarily, suffer the torments of the damned and, if they are not laid low by bites and hysteria, must sneak around like a CIA man in Hanoi.