Increased Turn Alternation by Woodlice ( Porcellio scaber ) in Response to a Predatory Spider, Dysdera crocata

The common garden woodlouse ( Porcellio scaber ) is known to alternate turns (correcting behaviour), but the function of this behaviour is only poorly understood. We investigated Hughes' (1967) hypothesis that this behaviour enables woodlice to escape efficiently from unfavourable environmental conditions by considering the effect of contact with a predator, a potentially unfavourable environmental condition that has not been nvestigated previously. In experiments, woodlice alternated turns more frequently after contact with a known predator of woodlice ( Dysdera crocata ) than after contact with cotton wool or a nonpredatory arthropod (housefly, Musca domestica ). &nbsp