Scientists at the Palacky University in the Czech Republic have discovered that common rough woodlice (Porcellio scaber) also display individual personalities similar to larger animals such as dogs, cats and horses.
Palacky researcher Dr. Ivan Hadrian Tuf and his colleagues at the university conducted experiments on woodlice to find out how the isopods would react to various stimuli such as prodding, squeezing and being dropped. They found out that each woodlouse responded differently to the actions, with some of them becoming bolder and others more timid.
The researchers said that considering different influences, including the isopods' body size, the woodlice showed behaviors that correspond to the definition of "personality."
When the woodlice were faced with a threat, they responded naturally by curling their armored bodies to feign death. Their segmented bodies allow them to safely tuck away their antennae and legs and leave their hardened carapace to protect them from attack.
Tuf and his team, however, noticed that some of the isopods were more or less willing to take on its defensive strategy of tonic immobility (TI), choosing to stay curled up longer than others.
This behavior among the woodlice remained consistent throughout different tests, and even after the experiment was conducted five more times over a period of three weeks.
Tuf said that some of the woodlice were consistently bolder (short TI), while others were more shy (long TI).
He explained that aside from the varying endurance level of TI between different body size groups of woodlice, he and his team also observed patterns of personal behavior in all of the isopods involved in the study.
Tuf added that rough woodlouse is the first terrestrial isopod species with recorded personality traits.
Personality trait among animals is often defined as having characteristics of individual behavior that remain consistent over a period of time in response to various situations.
While many people believe that woodlice are insects, they are actually considered isopod crustaceans similar to lobsters and crabs.
For their study, the Palacky researchers collected hundreds of woodlice from different parks and gardens in Kutna Hora.
The isopods were then placed in boxes where the researchers subjected them to gentle nudging, grabbing with forceps and dropping from a height of more than three inches.
The most common defensive strategy of woodlice is curling, although there are other methods that they use. In their experiment, around 77 percent of the isopods preferred to run away from the threat or use their foul-smelling chemical weapon.
Tuf and his colleagues noted that they were not able to determine whether the personalities of woodlice change over time.
The findings of the Palacky University study are featured in the journal ZooKeys.
Photo: Woodlouse | Flickr