GrrlScientist is an evolutionary biologist, ornithologist, aviculturist, birder and freelance science and nature writer. A native of the Pacific Northwest, she relocated from Seattle to NYC with her parrots after earning a BS in Microbiology (emphasis in Virology) and PhD in Zoology (Ornithology) from the University of Washington. In NYC, she was the Chapman Postdoctoral Fellow at the American Museum of Natural History for two years, pursuing part of her "dream" research project by reconstructing a molecular phylogeny of the parrots of the South Pacific islands. GrrlScientist and her five parrots are currently relocating to Germany, where she will continue writing her blog while also writing a book and learning German. (Meanwhile, her parrots will continue to nibble on her extensive personal library.) If you appreciate GrrlScientist's writing, you can help pay her living expenses by hiring her to "blog" your conference, speak at your club or write articles for your publication (or by clicking on the Paypal button below). If you read an essay on this blog that you especially enjoyed, please nominate it for inclusion in 
As some of you know, I live with a large group of cockroaches that boldly infest my apartment, along with those of all my neighbors. Call me crazy, but it always seemed to me that the smaller, more numerous, German cockroaches, Blattella germanica, made decisions together, or they appeared to at least consult with each other before hauling off my refrigerator as a well-organized team. But several scientists confirmed my suspicions today when they published their research suggesting that cockroaches are democratic group thinkers.
Cockroaches cannot communicate vocally, but it's known that they are very sensitive to chemical and tactile cues -- so much so that they can identify each individual's home colony simply by touching antennae. Antennae touching allows the insects to learn about each other through interpreting each other's chemical cues, similar to butt-sniffing in dogs.
José Halloy, a co-author of this study, tested the insects' decision-making abilities by placing them into an enclosure containing three shelters (pictured, above). He then documented how the cockroaches divided themselves up between the shelters. After frequent antenna probing, touching and other interactions, the cockroaches divided themselves up perfectly within the shelters. For example, if 50 insects were placed in a dish with three shelters, each with a capacity for 40 bugs, 25 roaches huddled together in the first shelter, 25 gathered in the second shelter, while the third was left vacant.
But when Halloy and his colleagues changed this setup such that there were three shelters, each with a capacity to house more than 50 insects, they found that all of the cockroaches moved into one house together.
This research shows that a balance exists in cockroach society between cooperation and competition for resources.
Halloy explained that "cockroaches are gregarious insects (that) benefit from living in groups. It increases their reproductive opportunities, (promotes) sharing of resources like shelter or food, prevents desiccation by aggregating more (humidity-conserving bodies) in dry environments, etc. So what we show is that these behavioral models allow them to optimize group size."
This research was published this week in the top-tier journal, Proceedings of the National Academy of Sciences.
Thanks, Dawn!
Comments
Fascinating! Related:
http://www.duke.edu/philosophy/bio/assets/team_agency.pdf
http://www.duke.edu/philosophy/bio/assets/evol_group_action.pdf
Posted by: coturnix | March 30, 2006 11:47 PM
After living overseas with these creatures, I find all this very spooky!
Posted by: Dawn | March 31, 2006 12:29 AM
Any sci-fi channel B-movies with social cockroaches in the making?
Posted by: coturnix | March 31, 2006 12:55 AM
As a gratuity I pass on my favorite roach-control system, proved over and over in the hot, humid, and buggy environs of Houston: 1 part cornmeal to 1 part boric acid powder. Dead roaches will be seen everywhere. Place in shallow containers along walls, in corners, and in enclosed spaces under sinks.
Posted by: biosparite | April 1, 2006 1:38 PM
I recently took a wide mouth fruit jar and put about 3 tbsp of used coffee grounds, about a half cup of water and placed the jar outside the house against the wall and inspected the jar a couple days later. There were about 30 dead roaches inside. That worked well so I placed several more jars in strategic areas and behold! it worked again. It appeared that they either drowned or were poisoned by the coffee.
Posted by: gary | July 5, 2006 3:01 PM