Halloy tested cockroach group behavior by placing the insects in a dish that contained three shelters. The test was to see how the cockroaches would divide themselves into the shelters.
After much "consultation," through antenna probing, touching and more, 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, and the third was left vacant.
When the researchers altered this setup so that it had three shelters with a capacity for more than 50 insects, all of the cockroaches moved into the first "house."
Halloy and his colleagues found that a balance existed between cooperation and competition for resources.
He explained to Animal Planet News, "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 in dry environments, etc. So what we show is that these behavioral models allow them to optimize group size."
The models are so predictable that they could explain other insect and animal group behaviors, such as how some fish and bugs divide themselves up so neatly into subgroups, and how certain herding animals make simple decisions that do not involve leadership.
David Sumpter, an Oxford University zoologist, told Animal Planet News that the new study "is an excellent paper."
Sumpter continued, "It is important because it looks both at the mechanisms underlying decision-making by animals and how those mechanisms produce a distribution of animals amongst resource sites that optimizes their individual fitness. Much previous research has concentrated on either mechanisms or optimality at the expense of the other."
For cockroaches, it seems, cooperation comes naturally.
Primary Classification: Blattaria or Blattodea (Cockroaches)
Location: Tropical regions worldwide
Habitat: A variety including leaf litter, bat caves, bromeliads, households and the splash zone of waterfalls.
Diet: A wide variety including decomposing leaf litter and fecal matter.
Size: From 0.4 to 3.6 inches in length.
Description: Dark, earthy colors; flat, oval-shaped body; long antennae; sensory bristles that extend posteriorly from the abdomen; winged or wingless
Cool Facts: There are at least 4,000 known species of cockroach. They have a variety of bacteria and protozoans in their gut that enable them to feed on decomposing matter, thus allowing them to play an important role in their respective ecosystems.
Conservation Status: Common
