Active Antennal Searching Suggesting Anticipatory Capability in PiIl Bugs (Armadillidium Vulgare)

This research shows that pill bugs can actively search for stimuli anticipating elicitation of adaptive behavior in critical conditions. The bugs were placed respectively onto an annulus-shaped substrate surrounded by water. Small obstaclesw. ere introduced at regular intervals in the middle of the annulus. They moved along the edge of the water, touching the obstacles with their antennae repeatedly. Moving along the water is dangerous for them as they risk drowning. Under such a critical condition, they demonstrated an adaptive behavior : mounting the obstacles. We further investigated the time series of antennal touching time on the obstacles, which can be assumed to be related to searching of stimuli. The log-log plots of the cumulative frequency distribution of the touching times showed a power law distribution.