According to researchers at the Free University of Brussels, individual cockroaches have their own personality and display individual character traits.

The team studied groups of American cockroaches (Periplaneta americana) and their reactions when exposed to light. For each trial, 16 individually tagged roaches were released into a round area located beneath a bright light. Each area contained two ‘shelters”.

After release, the insects given three hours to orient themselves in the new space. Their activities were monitored by camera and by tags on the back of each insect. The chips were linked to a computer which tracked the movements of each individual as it moved in the artificially constructed environment.

The same experiment conducted repeatedly over the course of three months.

“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,” Issac Planas, the lead researcher on the project and a PhD student at ULB told Reuters.

The goal of the research was to examine variances in group behavior and decision making. Cockroaches are widely studied insects, they are known for their decision making and problem solving abilities. However, they are also known for an aversion to bright light and their preference for groups and shelter.

The likely, expected, response to the situation was that all of the insects would rapidly move into the shelters. Ultimately, this was the case but the time it took for all of the roaches in a test area to move into a shelter varied greatly, according to the researchers.

According to Planas, the vacation was due to differences in individual personality and behavior.

If one roach moved rapidly to the shelter, it increased the likelihood that others would follow and reduced the total time that the group would take to reach the shelter. However, the movement of one insect did not incite a group response. One cockroach’s decision might influence others, but ultimately each responded individually.

This, according to the researches, distinguishes cockroaches from more hive oriented species such as ants and termites. Planas believes that the findings could shed light on other individualistic animals.

“We have a group of equal individuals that reach a choice, can have consensus decision making as we can see in sheep, bats, some monkey species, fish, birds, for example, or also humans in this case,” said Planas.

The most surprising thing, according to the researchers, was that each group would ultimately reach consensus. While individuals might exert their own personalities, regardless of the combination of personalities, all of the animals would end up in the shelters.

“The fact, and we didn’t expect it, is that they always reach this consensus. So we expected that some groups have more trouble than others to resist consensus or to choose a shelter, but at the end, no, they always finished aggregated. So it is something really inside the individuals or in the cockroaches. So that was really, that was amazing,” Planas explained.

The research team believes that the individual personalities of the cockroaches could help to explain their survival skills and ability to adapt to new situations. Some of the braver insects venture into new territories while the bulk of the population waits to see the outcome and find out if the new area is safe.

The next step for Planas is to study how individual behavior and learning experiences impact group behavior.