Simultaneous Versus Sequential Settlement in Territorial Species

Abstract

Although it is often assumed that more territory owners settle if they arrive at a habitat simultaneously than if they arrive sequentially, the empirical data on this question are both equivocal and contradictory. In this field experiment, juvenile territorial lizards were released either simultaneously or sequentially into the same patches of habitat. In five trials in as many patches, virtually the same number of lizards settled when they were released simultaneously as when they were released sequentially. Detailed behavioral studies indicated that previous settlers had both attractive and repulsive effects on settlement by newcomers. New arrivals that were attacked at high rates were less apt to settle than those attacked at lower rates, and newcomers were attacked 10 times more often in the sequential than in the simultaneous trials. However, those new arrivals that were attacked at relatively low rates initiated more fights and chases and tended to settle at higher rates when in a sequential situati...