Unlike ants and termites, individual cockroaches exhibit dynamic character traits, such as bravery and sociability. This may explain why cockroaches are such excellent survivors, capable of adapting to inhospitable and often unpredictable environments.
This research was led by entomologist Issac Planas who studies the behavior of the American cockroach at the Université Libre de Bruxelles. His work provides evidence for sheltering behavioral personalities in the gregarious cockroach. Reuters reports:
"Cockroaches are a simple animal, but they can reach a complex decision. So with little information, with little interactions, only knowing if I have a partner here or not, only with this information, they can make complex decisions," he said.
As Planas explained, the purpose of the experiment was to look at variances in group behavior and the way the group came to a decision. Cockroaches are known for their aversion to light, but also for their affinity for protection and groups. All of these preferences influenced each cockroach's decisions in the arena.
As a result, while it might seem probable that they would all quickly gather under the shelters, the study showed that the amount of time it took for the entire group of roaches to settle under a shelter varied. Planas attributed this result to the differences in individual personalities and behavior: if one roach was quick to settle under a shelter then it might encourage others to do the same, reducing the total amount of time needed to achieve the end result.
Even though one cockroach's decision could influence those of others, Planas says they're still ultimately responsible for their own choices. And even though the cockroaches have individual personalities, they still exhibit a collective personality at the meta-scale.
In future, Planas wants to study how individual cockroach behavior and learning affects group mentality.