RESPONSE OF THE ABORIGINAL HOUSE MOUSE MUS-SPRETUS LATASTE TO TUNNELSBEARING THE ODORS OF CONSPECIFICS

The behaviour of wild-caught Mus spretus towards tunnels previously oc cupied by conspecifics, and to the conspecifics themselves, was examin ed to test whether (1) willingness to investigate and enter tunnels co rresponded to the predictions of territorial avoidance, and (2) exposu re to substrate odours primed a defensive response to the odour's dono r. Adult males and females were provided with a choice of a clean tunn el versus one that had been occupied by themselves, by a conspecific f rom the same, a neighbouring or a distant area, or by a woodmouse, Apo demus sylvaticus. Mesh caps initially prevented tunnel entry while inv estigation was measured, then they were removed to record choice of en try. Subsequently, mice met the odour's donor in a neutral arena. Almo st all aggression was between mice from different capture areas and af filiative behaviour was between those from the same area. Conspecific odours attracted more investigation than clean tunnels, although odour investigation varied according to the subject and donor's sex and the ir relative capture areas. Mice investigated then avoided entering a n eighbour's tunnels, consistent with predictions of territorial avoidan ce. Provided with conspecific odours from the same or a distant area v ersus a clean tunnel, mice generally entered whichever tunnel they had preferred investigating before the tunnels were opened. Regardless of capture area, mice that entered a scented tunnel were significantly m ore defensive on encountering the donor than those that entered clean tunnels, especially towards female donors. This suggests that mice ent ering an apparently occupied (scented) area were primed to display sub missive behaviour towards a potentially dangerous resident.