Study Says Cockroaches Exchange Food Tips

LONDON (June 5) — Next time you raise your shoe to squish a cockroach, ponder this: You might be just about to kill the insect world’s version of a Zagat restaurant reviewer. Because according to new research published in the journal, Behavioral Ecology and Sociobiology, roaches behave like mini-restaurant critics, sharing recommendations about the best places to eat and pursuing gourmet tips offered by their bug buddies.
The study’s lead scientist, Dr. Mathieu Lihoreau of Queen Mary, University of London, told AOL News that while it was previously assumed that cockroaches foraged and ate alone, he had long suspected that this wasn’t true. “If you walk into an infested apartment, you’ll see them in a group,” he said. Lihoreau believed that this apparently social behavior could be a sign that the bugs were communicating with one another.
To test this hunch, Lihoreau and his team developed a simple experiment. Gangs of cockroaches were released in a 1-meter-square enclosure where they could choose between two identical slices of bread. “If they were behaving individually, then they would split into two similar sized groups and head to both food sources,” he explains. “But if they were communicating and cooperating, then they would aggregate on one slice of bread.”
The experiment was carried out with groups ranging from 50 to 200 cockroaches. While the lower-density swarms didn’t show a preference, larger groups repeatedly gathered around one of the two slices, with some 65 percent of roaches deciding to chow down on a single piece of bread. “What it means is that we have a collective decision by the cockroaches to select one food source,” Lihoreau says.
What’s still a mystery is how the bugs chatter among one another. Lihoreau says that it’s thought roaches use chemicals to communicate but, unlike ants, don’t leave a long-lasting scent trail on the ground that their companions can follow.
Instead, he suspects that roach “talk” happens when they touch, most likely through a pheromone found in their saliva or in the oil-like substance that coats their exoskeleton. So if one roach bumps into another chewing away on a cookie, it might think, “OK, this is probably a good place to dine.” And the more of his fellow bugs there are on the cookie, the greater the chance that the roach will stay and eat.
That swarm mentality acts as a form of self-defense, as a single roach surrounded by lots of other bugs faces a much lower risk of being picked off by a predator. In his next experiment, Lihoreau wants to expand on this theory and discover if herding also helps cockroaches identify “good” munchies, by placing one poisoned piece of food together with an untainted one in the enclosure.
By now you’re probably thinking, “OK, so now I know that cockroaches enjoy a meal together, but how does that affect me?” Well, if Lihoreau and his colleagues can identify the pheromone that brings the bugs together, they can also improve pest control. The alluring chemical could be used to tempt roaches into bug traps, or persuade them to gobble down poison.
Lihoreau, though, didn’t enter into this scientific field to slaughter his study subjects. “I’m one of the few people to examine cockroach behavior,” he says. “Most other scientists only want to know how to kill them effectively.” In fact, Lihoreau believes that these primitive bugs — whose earliest ancestors have been found in 350 million-year-old fossils — could teach us a valuable evolutionary lesson, by showing how “society” first began. It doesn’t take a Zagat or Michelin Guide to know that food is at the heart of it.