“The way this will affect the population is really complicated,” said Dr. Wada-Katsumata.
That’s because, despite the lockups, glucose-averse roaches are still finding ways to do the deed.
In lab experiments, Dr. Wada-Katsumata and her colleagues suggest that glucose-averse females are more skittish of males than wild-type cockroaches, which the researchers call the glucose-averse cockroaches. However, they also found that glucose-averse men seem to compensate for this by engaging in sex more quickly after offering his gift.
“The glucose-averse females could spend, say, three seconds eating the secretion of the male,” said Coby Schal, distinguished professor of entomology at the state of North Carolina and author of the study. “The wild-type male does not respond within three seconds. The glucose-averse man does.”
In fact, the researchers have evidence to suggest that all of these new stresses are causing changes in the chemistry of the glucose-averse man’s wedding gift so that he can potentially continue to attract women.
From a scientific perspective, the German cockroach sugar saga shows how humans can drive both natural selection—the cockroaches that survive our poison traps—and sexual selection—the glucose-averse cockroaches that no longer want to mate with cockroaches that still have sweet bites.
“I think this is what makes this so exciting,” said Dr. scale. “The idea that humans impose a very strong selection on animals around us, especially in our homes, and that the animals respond not only with physiological changes, but also with behavioral changes.”
The good news for consumers is that pesticide manufacturers have captured the enthusiasm of Dr. Wada-Katsumata and Dr. Schal for understanding the evolution of cockroaches, and that they are actively changing their cockroach-killing formulations to avoid glucose. But given how new this research is, it will take some time for those changes to make their way to the products on our shelves.
“The worst you can have as a product is a bait that won’t be eaten by cockroaches,” said Dr. scale.