My father, a calm and even-tempered man, seldom used expletives. But lying awake one night, I heard him enter the darkened bathroom, where he had left a cup filled with medicinal syrup to soothe his raspy throat, and then heard a horrible gargling noise, a crash of breaking glass, and a roar, “Holy Nellie!”
He had come close to swallowing a giant, sweet-seeking tropical cockroach that had been drowning in the glass, legs twitching. These persistent intruders were common in homes in the Philippines, where I grew up in the 1930s, and they did not indicate inadequate housecleaning.
Our cat, hunting the huge nocturnal creatures instead of mice, would leave neat piles of spiny legs and papery wings, the only cockroach parts with no nutritional value. Somehow, she had missed the one in the bathroom.
Almost everyone finds cockroaches repulsive and candidates for immediate extinction. But despite my father’s near-disaster, I don’t understand the fuss. As a biologist, I find them extraordinary creatures with a success story we’ll never match.
But a cockroach’s way of life is responsible for our aversion. Its flattened shape allows it to enter homes through the narrowest cracks; and as an omnivore, it finds every scrap of our food attractive. The powers of digestion in many species of cockroach are broadened by bacteria and one-celled flagellates living within the intestine.
Because cockroaches eat all kinds of organic matter, they enter garbage cans and step into refuse, which means their feet and excretions can carry bacteria to kitchen table or cupboard. Cockroaches can transmit dangerous human diseases, including cholera, typhus, tuberculosis, staphylococcus infections and dysentery. But all these diseases also indicate our failings in sanitation; so don’t heap too much blame on the cockroach. Our desire to exterminate them may be understandable, but we can at last admire their ability to survive – over millions of years.
Back in the time of coal forests, long before mammals, birds and reptiles existed, when trees were giant club mosses, and huge dragonflies clattered through the air, cockroaches were already well established in their ecological niche. A cockroach of 350 million years ago would look much like one today, perfectly comfortable living in warm and humid places that it was able to find thanks to temperature sensors on legs and antennae. They did fine long before apartments or restaurants, kitchens or bathrooms.
The world’s present cockroach population consists of almost 4,000 species, ranging from huge tropical flying ones (Nellies) to the inconspicuous little creatures found in the woodlands of New Hampshire and Vermont. Today’s cockroach is nearly the “perfect” insect in terms of anatomy and behavior. That it evolved to its present biological state so early in the history of insect life is extraordinary. Its design has been exactly right from primal days, and the adage, “If it ain’t broke, don’t fix it,” applies perfectly.
In addition to eyes that can detect the faintest light and movement, nocturnal cockroaches have a pair of exquisitely sensitive antennae and two abdominal cerci sticking out to the rear, as well as tiny sense organs in their legs, that can pick up the least vibration. These organs help explain why cockroaches flee so quickly when someone approaches. They run like the wind (and rustle when there are enough of them) with their slender but powerful legs. They need minimum endurance, for they almost immediately find cover. The large overlapping wings of many species allow them to fly, but in other species the wings serve as flat protective covering.
Cockroaches are prolific. Often a female is found carrying a partly extruded purse-like capsule that encloses two rows of a dozen eggs. Only after embryonic development is well underway does she drop the tough capsule into a protected spot, a crack or crevice somewhere. When nymphs are fully formed, one or two start wiggling, and this movement is transmitted, domino fashion, down the rows until all are active. The resulting rambunctiousness splits the capsule and the tiny nymphs scramble out.
Of the 4,000 kinds of cockroaches, barely half a dozen species enter our homes. The rest live mostly in damp, dark woodlands in warm latitudes. The cockroach’s ability to be active at night and escape and hide when threatened allowed it long ago to adapt to the most severe challenges. This wondrous animal is more successful in a biological sense than we can ever hope to be. Its future is bright.
Archy, the compassionate cockroach, created decades ago by newspaper columnist and poet Don Marquis, once implored (using neither capitalization, nor punctuation): “many a cockroach considers himself as beautiful as a butterfly have a heart o have a heart and let them dream on”
Holy Nellie!