/ 14 November 2015

Bite on this: Roaches to the rescue

The quality of the water in Khayelitsha's RR section is highly questionable
The quality of the water in Khayelitsha's RR section is highly questionable

It is the most perfectly evolved animal in existence. But, rather than lauding this remarkable achievement, our first reaction is to plaster it all over the sole of a shoe.

We hate its presence, as a signifier that the backlog in cleaning has got the better of us this week. And we associate its name with people below us, with xenophobic overtones. But the tiny, mighty cockroach is here to stay, with evolutionary tweaks that could make it the ultimate weapon.

It didn’t take long after humans detonated the first atomic bomb for talk to get around to the inevitable question: What can survive something so comprehensively destructive? Cockroaches. They outlived the dinosaurs, saw off plagues and heat waves and now find themselves negotiating the tricky space between being needed by humans and being sprayed to death.

This resilience has drawn the attention of inquisitive scientists around the world.

Prodding and zapping cockroaches is something of a morbid niche. The prodding has gone from the sensitive to the catastrophic, which the insect has taken in its stride. One laboratory in the United States chopped the heads off cockroaches and left the torsos in sealed containers. They lived for a month. Similar results have come from numerous other attempts at disfiguration.

Other scientists, no doubt taken by the hardy creatures, have tried to humanise the six-legged insects. These omnivores apparently have distinct personality types, also born out of evolutionary necessity. Shy ones hide away in the darkness – the word cockroach comes from the Latin for “insect that shuns light” – and live longer. Bold ones venture out and get rewarded with food and a mate, or get smashed by a shoe. To catalogue this behaviour, scientists put radio tags on cockroaches and let them wander around cages with electric fences in pitch darkness.

In an attempt to learn from cockroaches, scientists at the University of Cambridge have found that their jaws can grind five times more strongly than those of humans. “Ours is the first study to measure the bite forces of ordinary insects, and we found that the American cockroach, Periplaneta americana, can generate a bite force around 50 times stronger than its own body weight,” said lead author Tom Weihmann from the university’s zoology department in a study published in the journal Plos One on Wednesday.

To do this, the cockroaches unleash extra muscle fibres in their jaws and then gradually grind through their chosen meal.

Given their evolutionary advantages – and survivability – engineers in Texas have started wiring miniature computers into the nervous system of live cockroaches. This allows them to control the insects remotely, purportedly to send them into dirty and small places, such as sewers, to find faults. Luckily they are also incredibly clean animals, so can come out smelling of roses.

Given the plethora of faulty pipes shown up by the current water crisis, many South Africans might be able to see their way towards volunteering the colonies of cockroaches scurrying around their houses to a greater cause. Human and cockroach, united.