Repeated training does not improve the path integrator in desert ants

Desert ants, Cataglyphis fortis, return to their nest by means of path integration vectors. By using the reversal of these vectors, they approach previously visited feeding sites again. They adjust these vectors whenever outbound and inbound vector are set into conflict or when they make use of external cues. Here, we examine the influence of repeated training on the accuracy, precision, and straightness of outbound and inbound vectors. We trained desert ants to forage to and fro between their nest and a feeder and made sure that they relied exclusively on their path integrator. Neither the ants' outbound nor their inbound runs, which, in general, are straighter than the outbound runs, become more accurate, precise, or straighter during repeated training. Hence, repeated training does not improve the path integrator in desert ants.