FRANCE: According to a new study, individual cockroaches can be shy or bold. However, they alter their behavior to fit in with a group.
The new study has focused on cockroaches common to the U.S. It was found that the cockroaches behave according the social expectations of a group, even though they may vary in individual levels of boldness.
The concept of personality, something defined as a persistent behavior such as sociability, aggression, or daring, had previously been shown in a variety of invertebrates like spiders and octopi. Up until now, such observations had not been made with cockroaches.
Since the insects are social but not constrained to a leader-driven hierarchy, researchers based at the Université libre de Bruxelles in Belgium decided to use P. americana to study the differences between individual and group personality.
For the research, the scientists fixed radio frequency tags on more than 300 four-month-old male roaches sorted into groups of 16. Over the course of a week, the groups of light-averse insects spent most of their time in dark, with the exception of three evenly spaced three-hour sessions in an enclosed and brightly lit test environment that had two shaded areas for shelter.
The researchers found that some cockroaches were consistently shy and dashed to the shaded areas as soon as they were placed in the environment, while others took their time exploring the well-lit area during each of the trials. By the end of each trial, however, all 16 members of the group ended up under the same shelter.
The research concluded that there was a collective dynamic that dilutes the individual personality differences. This means that with the group, similar behavior occurs with each cockroach.
