In certain Asian countries, having roaches in the house is considered a sign of good fortune; only the rich, after all, have so much food that they can feed their families and cockroaches too.
The number of cockroaches that people of European descent are willing to tolerate, however, usually ranges from zero to none. A standard British text on the subject, for example, resorts to such unscientific terms as
”loathsome” and ”abhorrent” to describe the so-called ”domiciliary”
roaches.
There are many more species of cockroach in the world than most people think are absolutely necessary-3,000 or so. No one knows how many for certain, and, sadly, we may never know, because the vast majority of species dwell, endangered but as yet unidentified, in tropical rain forests. They have been successfully exploiting that environment for eons.
Ironstone nodules found near Illinois` Mazon Creek that date from the Carboniferous Period (roughly 250 million years ago) bear fossil remains of cockroaches that differ in only insignificant ways from the modern-day creatures.
As is the case with most large families, only a few species of the suborder Blattaria (which includes all cockroaches) have habits that make them pests. ”There were native cockroaches here when the Indians arrived; woodland species like the wood roach,” which is of the genus Parcoblatta, said Dr. Philip Nixon, an entomologist for the Illinois Natural History Survey and the University of Illinois Extension Service.
These roaches are adapted to Illinois` temperate climate and typically are found outdoors on the floors of our deciduous forests, sometime in wood piles. Except when winters are very cold, woodland roaches almost never invade houses, whose climate they seem to find too warm and dry.
That`s just as well. The wood roach is a largish insect-about one inch long. It is attracted to lights, so when the males try their wings during spring breeding season, flights of 100 feet or more can take them near, even into, houses. Said Nixon, ”You know it when one comes buzzing through the living room.”
Settling in
But the cockroaches commonly reviled as house pests are not native to Illinois. Their common names-the German cockroach, the Oriental cockroach, the American cockroach-suggest creatures of cosmopolitan origins. In fact, all the common pest species are creatures of the Mediterranean rim, specifically northern Africa; as civilization spread, so did roaches. Like humans, cockroaches have settled virtually every continent without ever straying far from the tropical environment of their ancestors.
Because it loves kitchens, the prolific German cockroach Batella germanica has embarrassed more housekeepers than bad cooking.
”If you have roaches in only one room of your house, it will be in the kitchen.” Why? They find food there, of course, but also moisture (condensate from cold water pipes inside the walls is a typical source) along with steady warmth and lots of crannies and crevices in which to hide-as close to a tropical forest floor as any environment (that doesn`t charge a health club membership) can get. ”They say that a happy roach won`t move more than 10 feet in a lifetime,” Nixon said.
The non-native species common in Illinois are somewhat less tolerant of variations in temperature and moisture, and thus are as picky in their choice of habitat as a new-home buyer shopping for the perfect suburb.
The Oriental cockroach would rather spend time in a catchbasin than in a king`s palace. The brown-banded roach is often found in offices. ”We`re not sure why,” Nixon said. ”It has possibly the lowest need for water among the non-natives. And it likes to hide in stacks of paper”-a trait the insect may have picked up from human bureaucrats.
Cockroaches do not nest per se, nor are they social insects like their relatives, the termites. But they do clump together in groups. A crack that has been visited by one cockroach will be visited by more, who will be attracted to it by the smell of its fellows. They so enjoy company that a live roach prefers to sit next to a dead one rather than sit alone. Nixon says that sticky traps such as roach ”motels” work best when there is a dead roach already in it.
Sweeping away myths
Because they are easy to raise, cockroaches have been extensively studied by scientists. But the public, alas, remains uninformed. For example, the presence of roaches is widely believed to be proof of slovenly housekeeping, but like most cockroach conventional wisdom, this is only partly true.
Sanitation is important in cockroach control, but while it may impress your mother, it won`t impress a cockroach. As Nixon explained, ”It is essentially impossible for a human being to starve a roach.” The insect is the very definition of ”omnivorous.” It eats everything human teenagers eat plus animal feces, wood, wallpaper, book bindings, paper paste and glues. Some species even devour the corpses of their own kind. (They are the ultimate recyclers.)
Effective anti-roach hygiene thus requires that every crumb be wiped up, garbage put into sealed containers, and supper dishes washed before the leftovers get cold. Leaving pizza on the counter overnight is like going on vacation and leaving your front door unlocked.
Many a nightmare has been triggered by another cockroach myth, usually expressed in the form of a maxim: ”For every one you see, there are a thousand more you can`t see.” It is quite true that you will not see more than a fraction of the roaches that may be sharing your dwelling. They are nocturnal, for one thing; for another, they are stay-at-homes-the original crevice potatoes.
Roaches typically feed only once every 24 hours. ”They spend the other 21 hours a day sitting,” Nixon said. ”Even during the night, maybe two-thirds of them aren`t active,” he added, and many of those that are active will be foraging unseen inside walls, beneath cabinets, etc. But Nixon estimated that for every cockroach you sight during the daylight hours there may be only 50 to 100 others lurking unseen, not a thousand.
Cockroaches are often advertised as carriers of dozens of diseases. There is no evidence that they directly transmit diseases dangerous to humans. And while they have bad manners for house guests-they stain everything with their excrement-they are as fastidious in their grooming habits as cats.
Cockroaches get dirty, but that`s because they share our human habitat. Because they frequent sewers, drains and food-handling areas, roaches collect and carry disease organisms that can be transmitted by physical contact with humans or their food. Most such diseases, like typhus, are a problem only where sanitation is woefully inadequate; in fact, most of the diseases that roaches can carry are no longer encountered in the U.S.
As Nixon put it, ”If you live in a place where typhus is common, cockroaches will be the least of your health worries.”
Battling encroachment
The chemical warfare waged against the cockroach costs millions, but even professional applications of licensed insecticides on a regular basis will not by themselves rid a building of a roach infestation. Less potent chemicals can work just as well. Boric acid (the crystalline powder used in diluted form as an antiseptic) is a wonderful roach killer: relatively cheap, safe to handle, and lethal for a year or more when spread in roach habitats as a dry powder. Boric acid is picked up on the insects` bodies, then ingested as they lick it off.
But boric acid works only when dry, and when it is dry it cannot stick to any but flat surfaces. It can also spread into food.
Some people reason that if a little boric acid is good, a lot of it will be great. To an animal the size of a cockroach, these piles of white powder are as imposing as the Indiana Dunes; rather than walk through them, they sensibly walk around them.
”The proper control of cockroaches requires an integrated pest-management scheme,” said Elliott Zimmermann of the Illinois Department of Energy and Natural Resources, which is working with Nixon and others to devise cost-effective and safe roach-control techniques. The management approach seeks to use no more insecticide than is necessary, starting with the least-toxic control method available, monitoring the results, and, if the roach population isn`t reduced, applying the next-most-toxic control.
In the case of cockroaches, a management approach starts with sanitation and exclusion: sealing baseboard cracks and pipe openings that provide access to a dwelling. The next step is selected use of chemical insecticides in spots where monitoring confirms the presence of the insect.
The state Energy Department is coordinating tests at selected Downstate restaurants. At one such location, Zimmermann said, the roach population shows no signs of rebounding a full year after all spraying has ceased.
New and exotic roach repellents and roach viruses are being tested in laboratories around the U.S. And because most pest roach species are sensitive to temperature changes, cold and heat can be effective non-toxic weapons.
Egg development slows and life expectancy shortens as the temperature drops; and a building can be fumigated solely with heat by raising the interior temperature in a closed building to 100 degrees for a few hours, using portable heaters. The insects can`t stand the heat, and so get out of the kitchen-permanently.
Humans are not the only predator species that threatens cockroaches. The larvae of the ensign wasp parasitize the eggs of certain species, especially American and Oriental cockroaches. Wolf spiders eat them, as do tropical lizards such as the gecko. House mice also like them. But if you have enough mice or wasps or lizards in the house to really make a dent in your roach population, they will themselves become pests.
It is often said, grudgingly, that if Homo sapiens ever destroys itself through environmental or nuclear catastrophe, cockroaches will take over the Earth. You might not be able to prevent that, but Nixon said you may be able to prevent them from taking over your home. By assiduously caulking and sanitizing and spraying, a diligent person can rid a house of roaches in six months.
Deroaching an apartment will probably take longer. ”If you live in a very large building,” he said, ”you might as well make friends with them. You`ll be moving out long before they will.”
