Cockroaches Evolving to Avoid Traps

 Roaches that are  more than usually hard to trap may be a variety that find sugar doesn't taste quite so sweet as bait anymore, a study suggests. Most cockroach baits cover poison in a layer of glucose or, basically, sugar. Some mutant German roaches, the most common species of pest found in houses, apartments, restaurants and hotels, now taste glucose as bitter, researchers said today in a study released in the journal Science. This change in palate enables them to avoid traps. A step in cockroach evolution that has scientists fascinated.

The scientists collected 19 roach populations, mostly from the US and Puerto Rico, to look at how common the glucose- spurning had become. They found seven populations that had the taste trait, said Coby Schal, a study author and a professor of entomology at North Carolina State University in Raleigh. He expects the numbers would have been higher had his group asked exterminators to send sample roaches from infestations that had been difficult to control by ordinary means.

 

"It's very important, in terms of effective pest control," Mr Schal said in a telephone interview. "It's not trivial. It's out there."
It is, in fact, necessary for our health and quality of living to control roaches and other disease spreading insects that infest buildings with huge populations. An infestation can get completely out of control.

Glucose is a popular ingredient in poisonous baits, the study authors wrote. In normal German cockroaches, the glucose creates responses in the sugar neurons. In the mutant roaches, the glucose triggers the bitter taste bud receptors, prompting the insects to avoid the sugar.
The mutant roaches didn't stay away from all sugars. They would still eat fructose (fruit sugar). And they paid a price for their modified diet: they grew more slowly than glucose-chomping brethren.

Using fructose as a bait has drawbacks. Regular high-fructose corn syrup is 40 to 50 percent glucose, Mr Schal said. Refined high fructose corn syrup, which is 90 percent fructose, is more expensive, he said. Other foods cockroaches like, such as tuna fish, can be substituted for glucose as a bait to combat the mutant taste populations. The tradeoff is the smell of tuna in the house, Mr Schal said.
"It's always a compromise in formulating baits," he said.
Peanut butter has served as a good short-term bait solution, as roaches are attracted to the food and it doesn't require glucose to be effective, he said.

Insects are evolving and adapting to their world more rapidly than we can kill them. Sadly, other species in the world can't do the same.  Humanity is destroying the network of living things that comprise our life support system. While this sawing-through-the-branch-we’re-perched-on is largely unintentional, world leaders can’t say they didn’t know what’s been happening: 123 countries promised to take urgent action in 2003 but have done little to stem the rising tide of extinctions in what’s known as the extinction or biodiversity crisis.

Species are going extinct at 1,000 times their natural pace due to human activity, recent science has documented, with 35 to 40 species vanishing each day, never to be seen again. But cockroaches adapt and come back stronger than ever. Perhaps someday it will be a planet solely of cockroaches. I hope their politicians are not as foolish as ours.