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Why is it so hard to kill a cockroach with your shoe?

The Cockroach Papers by Richard Schwied is an interesting book if you are looking to learn more about biology or evolution. Cockroaches are built for survival no matter what the world throws at them. Their ability to adapt is just amazing.

Here are some of my notes from the book.

Food and Water
German cockroaches, Blattella germanica, the most common domestic roach in the United States, have been observed to live 45 days without food, and more than two weeks with neither food nor water.

Cockroaches will eat almost anything including glue, feces, hair, decayed leaves, paper, leather, banana skins, other cockroaches, and dead or alive humans. They will not, however, eat cucumbers. They are particulary fond of dried milk around a baby’s mouth.

The roaches are not confined to any particular environment and live in a tremendous variety of places, from underneath woodpiles in Alaska to high in the jungle canopy in the tropics of Costa Rica. They are even found in the caves of Borneo and under the thorn bushes in arid stretches of Kenya. Wherever they live, they are masters at surviving. They are, Schwied writes, “undeniably one of the pinnacles of evolution on this planet.”

Why is it so hard to kill a cockroach with your shoe?
Schweid observes that “when a cockroach feels a breeze stirring the hairs on its cerci, it does not wait around to see what is going to happen next, but leaves off whatever it is doing and goes immediately into escape mode in something remarkably close to instantaneous fashion.” Studies show that a cockroache can respond in about 1/20th of a second, so “by the time a light comes on and human sight can register it, much less react by reaching for and hoisting something with which to squash it, a roach is already locomoting towards safety.”

Blood
Cockroach blood is a pigmentless, clear substance circulating through the interior of its body, and what usually spurts out of a roach when its hard,outer shell—its exoskeleton—is penetrated or squashed is a cream-colored substance resembling nothing so much as pus or smegma.

Brains
Cockroaches have two brains—one inside their skulls, and a second, more primitive brain that is back near their abdomen.

Copulation
Schweid says “Pheromones, chemical signals of sexual readiness, operate between a male and female cockroach to initiate courtship and copulation. A sexually receptive female assumes a posture with her abdomen lowered and her wings raised, and gives off a pheromone that attracts males.” If he finds a virgin female, a male cockroach after some antenna rubbing foreplay will turn away from the female and raise his wings, “an invitation to her to mount.”Copulation frequently lasts an hour. After sex, female cockroaches store the sperm and use them as needed. The sperm may last her a lifetime.

“The evolutionary strategy employed by cockroaches to reproduce is considerably more efficient than that employed by humans.” Oddly, there are certain species of cockroaches that can, at least for a generation or two, reproduce without any sperm. Schweid says “the females unfertilized eggs will develop and hatch—always producing new females.”

Partying
Betty Faber, the former staff entomologist for the New York Natural History Museum, says “Females go to bed—by which I mean disappear back to the harborage—at night earlier than males.”

Socialness
Schweid writes, “cockroaches, while not social insects in the entomological sense of bees or ants with clearly assigned tasks that benefit the whole community, do clearly take pleasure in the company of other roaches, and the aggression pheromones draw them together, eliciting their effects regardless of the sex or age.” Cockroaches reared singly develop more slowly and take longer between molts than do those reared in a group. Although those groups can be too big “just as development is delayed in young cockroaches if they are isolated, over-crowding also extends the time between molts. So there is yet another kind of pheromone, called a “dispersal pheromone,” and it serves as the chemical signal that it is time to look for a new, slightly roomier harborage. This chemical is found in the insects’ saliva, and has just the opposite effect of the aggression attractant, in that it repulses cockroaches and causes them to look elsewhere for harborage.”

Radiation
In case you’re thinking we can just nuke the little critters you should know that cockroaches survived the atomic bombs test blast at Bikini. “There is such a thing as a lethal dose of radiation for a cockroach, but it is a lot higher than our own.”

Predators
“While few humans may eat them, the roach has both external and internal predators and parasites. There are centipedes that have a primary diet of cockroaches. Mantises, ants, and scorpions will eat them, as will a variety of larger animals including toads, frogs, possums, hedgehogs, armadillos, mongooses, monkeys, lizards, spiders, mice, cats, and birds”

Sleeping
Roaches are nocturnal and pass their days sleeping.

Male aggression
“Cockroaches, like so many other species including our own, have male aggression rituals. They have their own inventory of aggressive behaviors, a scale of conflict that begins with threatening postures. Beyond that they graduate to antenna lashing—a form of which is also present in male/female encounters to determine if a female is sexually receptive–and biting. Sex and territory seem to be the primary motivations for fighting between male cockroaches: These clashes never end in death, but always in the retreat of one fighter.”

Trapping a cockroach
“Stale while bread moistened with warm, slightly soured beer” is the most reliable and effective. “This is typically placed at the bottom of a small jar—a Gerber’s baby-food jar, say—around the interior rim of which a petroleum jelly like Vaseline has been applied. The cockroach can climb in from the outside but can’t climb back out.”

What should you do if you get a cockroach stuck in your ear?
“It is, according to all accounts, painful and horrifying, although a little mineral oil or lidocaine sprayed into the ear is usually enough to dislodge the intruder.”

Exterminators
Exterminators primarily employ two methods to kill the cockroach: gas and gel. The gel is way more effective but many still rely on the spray. Why? “The major problem that exterminators have with the gel is that it has no immediate knockdown effect.”

John Wickham, an English pest control consultant defined knockdown as: “The inability of the insect to move in a sufficiently coordinated manner to right itself and progress normally.” When a roach eats gel bait—the safer of the two methods—it heads home before the active poison kills it.

“Customers who are paying $75 an hour like to see these roaches struggling to get up, in agony and convulsions, and the sprays, with substantial knockdown effect, provide them that gratifying visual reassurance that the problem is being solved and that they are getting their money’s worth.

It’s unlikely this poison will have much long term impact. “Almost as soon as an effective poison goes into widespread use, cockroaches begin to develop Resistance. And, typically, the most efficacious products developed, those that do the best job, turn out to be more detrimental to our own health than are the roaches.”

If you want to learn more about cockroaches read The Cockroach Papers.