Is signalling of fighting ability costlier for weaker individuals?

Using a simple model of signaling of fighting ability, I demonstrate that; (1) conventional, cost-free, signals of fighting ability can be an ESS, (2) signals with significant costs can be used at ESS as long as they are used to indicate weakness rather than strength, (3) that if a set of signals is used to indicate a set of fighting abilities through their costs, they must decrease in cost for stronger signalers. The reason for this is that individuals of higher fighting ability have less to gain by avoiding escalated contests, and are thus more sensitive to signal costs. These results are of particular relevance to badges of status and other simultaneous signals used to settle contests over minor resources. (C) 1997 Academic Press Limited