Cockroaches: know your enemy

FeatureThey thrive in the heat, are masters at hiding and can live for a month without eating. Why, they can even survive for days without a head.

Katie Edwards / Debut Art

They thrive in the heat, are masters at hiding and can live for a month without eating. Why, they can even survive for days without a head. Yes, they're tough, writes Jerry Langton... but not invincible. Amina has a problem. The Abu Dhabi-based nanny who lives in Al Bahia tries to stay as clean as possible, but still she has what she considers to be the worst of all pests. "I am embarrassed to admit it, but I have cockroaches," she told me, asking me not to use her real name. "Not many of them, but even one is just too horrifying to deal with." She's tried to get rid of them, but they just keep coming back. "It's like they're invincible," she says with a tone of resignation.

But there is hope for her. To control cockroaches, you have to know your enemy. There are two kinds of cockroaches in the UAE. Actually, there are probably more. In fact, there are more than 4,000 species of cockroach, but only four are known to seek out human residences as habitat. The only ones you're likely to run into here, unless you look very, very hard, are American cockroaches, which did not originate in America, and German cockroaches, which aren't even found in Germany.

Scientists say cockroaches emerged in basically the same form as they are now about 300 million years ago. They are large by insect standards ? some can be up to 9cm long and weigh more than 30 grams, although most are no bigger than a postage stamp. They have wide bodies, small heads and two sets of wings, and they use the hard outer sets as armour. While they can fly short distances, cockroaches prefer to run from trouble and are among the fastest of all insects. They communicate with pheromones - scented hormones - which explains why places infested with cockroaches have such a strong, unmistakable smell. They thrive in the heat - preferably 30C or higher - but they must have access to water.

Like most people affected by cockroaches in their homes, Amina has turned on her apartment lights to see cockroaches scatter. While many people believe cockroaches recognise humans as danger and flee, experts say they are running from the light. With as many as 2,200 lenses in each eye, the insects, nocturnal by nature, are exceptionally light sensitive. Candles look like rows of floodlights to them; lightbulbs are like looking straight into the sun. They live in large groups and are good at hiding, so if you see one, it's more accurate to say it is representative of many you don't see, as opposed to the one you see being a scout or pioneer.

Cockroaches will eat just about anything. But the American and German varieties have a particular fondness for the very things we like: carbohydrates, sugars, meats and oils. The big difference is that the roaches' simple digestive system and mouth give them a taste for food that is rotting or fermenting. So while cockroaches don't communicate diseases to humans, they have been known to carry dangerous bacteria from decaying food (like yesterday's chicken) to fresh food (tonight's pizza), which has resulted in various types of food poisoning, dysentery and other gastrointestinal problems in humans and pets.

But if there's no human food around, cockroaches will make do with things like bookbinding glue, candle wax, human hair or even each other. And even if none of that is available - as in laboratory studies - cockroaches can survive up to a month without eating. That's not the only remarkable feat of survivability these little guys perform. They can survive without air for 45 minutes, so forget trying to drown them. And as Amina and others can attest, you can step on a cockroach, hear a satisfying crunch, lift your foot and see the pest scoot away seemingly unharmed. That's because the hard outer wings protect the animal's internal organs from pressure.

They are tough little things, but there are ways to rid yourself of them. The first step, according to Steve Jacobs, an American insect expert who researched and wrote extensively about cockroaches at Penn State University, is to make your residence less appealing to them. "Modifying the interior environment - removing food, moisture, and harbourages available to cockroaches - is the first step in treatment," he says. "Eliminating cockroach harbourages involves caulking in closets and cabinets, caulking under the sink, etc, or making similar structural repairs in the kitchen, bathroom, and other areas of the house."

The key is food. It is essential to discard unwanted food quickly. Pets should also be fed under supervision and pet food should never be left out overnight. Amina, following the advice of a friend, has seen a marked improvement simply by storing all food - even things that don't spoil like breakfast cereal, olive oil and dried pasta - in her refrigerator overnight. While making these sorts of environmental changes won't kill any roaches, it will make your residence less appealing. Cockroaches, great lovers of luxury, will be persuaded to move to more appealing digs - like your neighbour's apartment.

Actually killing the little beasts is another story altogether. Keep in mind that this is an animal that can survive for days without a head. Jacobs recommends against using sprays or aerosol cans. Cockroaches simply run away from such threats, returning when the coast is clear. A better solution is the use of astringent chemicals. Cockroaches need to be covered in oil to survive, so chemicals that dry them out can be lethal.

According to Jacobs, the best bets are silica gel (the same stuff found in clothes to keep them fresh), diatomaceous earth (which can be found in shops as a slug and snail repellant) or boric acid. Available in powder or chalk form from pharmacies and hardware stores, boric acid can be used to draw lines in places of high cockroach traffic. When the pests cross it, the powder sticks to their bodies, the oil is absorbed and the insects die. If you don't know where they are, put out some food they can't resist - like a chocolate chip cookie - and surround it with boric acid. It only takes a tiny amount of astringent to kill cockroaches, so don't overdo it. While none of the chemicals are strictly toxic to humans or pets, they can make a child or small animal feel ill because of dehydration, especially in warm climates such as Abu Dhabi's, so don't use it where either might come into contact with it.

"Unfortunately, cockroach season in Abu Dhabi is all year round," says Frieda D'Souza, an employee at Bright Pest Control and Hygiene Services. "I'd say about 75 per cent of homes here have cockroaches." Homes that keep their garbage outside are at risk of attracting cockroaches; but so are homes that keep it inside, D'Souza explains, so no one is really safe. But armed with a small piece of chalk and the knowledge that cockroaches are tough, but not invincible, Amina can rest assured that her embarrassing little problem doesn't have to be permanent.

The pest-removal services D'Souza's company offers can rid households of the pests "forever and ever" she assures, "but we only offer a six-month guarantee". Additional reporting by Jessica Hume