Path integration in Blattella germanica (L) (Dictyoptera : Blattellidae): orientation and distance.

Path integration means that the animal is continually computing its present location from its past trajectory and that it is thus able to return to it s starting point along a direct route. An animal must continuously compute its home vector pointing toward its shelter. The two components of path int egration (orientation and distance) were analysed in a nocturnal insect, Bl attella germanica (L.). Homing behavioural tests were made in total darknes s. After a passive rotation, some larvae behaved as though they had not bee n rotated and took the direction they have followed to return to their shel ter before the rotation. Furthermore, when the shelter was not in the area indicated by the home vector, the larvae adopted a systematic search strate gy. The path was divided into 3 phases: a short, rapid and linear pan, foll owed by an arrest and then a long and slower part looping around the arrest position. Our data show that cockroaches use path integration to orient an d to estimate the distance they have to travel to reach their shelter in th e absence of visual landmarks.