TERRITORY ACQUISITION IN LIZARDS .3. COMPETING FOR SPACE

Juvenile Anolis aeneus lizards were released into patches of microhabi tat in the field, and their social interactions and space use recorded throughout the settlement period. Two hypotheses about the role of so cial interactions in space acquisition were tested: (1) settlers win s pace by winning contests and (2) settlers win space by persistence. Re sults supported the second hypothesis. Juveniles did not acquire the a reas in which they won interactions with opponents, and in the vast ma jority of dyads, both the winner and the loser subsequently avoided th e location of their first encounter with one another. A second set of analyses focused on 'space transfers', in which one settler gained pos session of space that had been used by its opponent before they began to interact with one another. Subordinates were as successful as domin ants at taking space from their opponent, and space transfers by domin ants and subordinates were virtually identical with respect to estimat es of the costs and benefits of space acquisition. Dominants acquired space by repeatedly chasing subordinates, and the amount of space that transferred from subordinate to dominant was positively related to th e rate at which the dominant attacked the subordinate. Conversely, sub ordinates took space by persisting in the face of repeated attacks by dominants, and the amount of space taken by a subordinate was inversel y related to the rate at which the subordinate was attacked by the dom inant. Overall, dyads with space transfers interacted at higher rates for a longer period of time than dyads without transfers, and dyads wi th transfers were more likely to end up with overlapping activity area s than were dyads that resolved their disputes without taking space fr om one another. Two factors had independent effects on the probability that a dyad would engage in a transfer: (1) spatial overlap when the pair first encountered one another and (2) contender pressure in the p atch of territorial habitat.