Cockroaches' Sudden Evolutionary Trick Makes Sugar Bitter
It's said that cockroaches have the ability to survive the nuclear apocalypse. Indeed, the insect has employed numerous evolutionary tricks during its 350-million-year history on Earth. One of the most surprising is that German cockroaches appear to have evolved a mechanism to make sugar taste bitter. The research may be apply to fields as diverse as malaria treatment and health problems in humans.
According to the Los Angeles Times, exterminators, who now prefer to be called pest management professionals, used to fight cockroaches by spraying insecticides on baseboards in homes. However, out of fears for the safety of children and pets, they switched to a new method: bait traps. The pest management professionals would place bait traps in cupboards and on floors that contained poison and sugar. In theory, the cockroach would eat the treat placed in the bait trap, thinking that it was a sugary sweet, return to its nest and die. Hopefully, too, the cockroach's relatives would cannibalize it and receive a taste of the poison as well.
That method worked - for a time. But in the beginning of the 1990s, it stopped working, as cockroaches appeared immune to the traps. In itself, that was not a concern; according to the New York Times, pest management companies are constantly developing new poisons, since animals frequently become immune to their effects, just as bacteria become resistant to antibiotics. However, it became apparent that the issue was not just the poison - it was the glucose used as bait. Since then, pest management professionals have switched to fructose, which has appeared to work splendidly ever since. Still, researchers could not understand how glucose could have lost its potency for cockroaches.
Finally, researchers spotted the answer. LiveScience reports that the researchers sedated the cockroaches and attached electrodes to the hairs that cockroaches use to taste. In behavioral tests, it was easy enough to see the difference: normal cockroaches love the taste of a sweet, sticky jelly. In evolved German cockroaches, the type that are so familiar to apartment-dwellers, they jump back at the taste. The electrodes provided the answer: the cockroaches' bitter cells are activated with the taste of glucose. Sugar tastes bitter, not sweet to them.
It is possible that the evolutionary mechanism is a rapid form of evolution in response to the bait traps. It is also possible that the response existed long ago in cockroaches; some toxic plants are bittersweet, and the insects would have needed to evade them long before humans appeared. Regardless, the research is plainly useful. Some mosquito behaviors have changed mysteriously in recent years, avoiding walls treated with insecticide. If researchers can discover what has happened, it could be useful in the fight against malaria, a far more dangerous enemy than the cockroach.
It could also be helpful for human public health. Avoiding materials that are harmful to human health could also cut down on incidences of various conditions, like obesity or diabetes, or addictions, like alcohol and drugs.
The study was published in the journal Science.