A model for a population-game with multiple asymmetry is studied, in which
the participants are assumed to be different from one another both in size
and in status as owners or non-owners of a territory. Only owners can repro
duce, hence natural selection is assumed to operate in favor of the increas
e of ownership-time. Conditions for the evolutionary stability of the Bourg
eois Principle of owner-priority, despite difference in body size, are char
acterized. It is shown that ownership-priority tends to be at least partial
ly replaced by strength-priority as the availability of habitats, the expec
ted longevity of potential intruders and the harm inflicted on the loser of
an aggressive confrontation decrease, and as the expected longevity of the
owner increases. It is further established that the combined effect of all
these parameters can be characterized by a single parameter, referred to a
s the concord coefficient of the population. Finally, when this parameter r
eaches a certain critical level, only strength-priority can prevail. If the
concord coefficient decreases below this critical level, no priority-rule
can remain stable in the population, in which case aggressive confrontation
s cannot be avoided, at least in certain situations. In this case, it is sh
own that aggression emerges first among low-rank individuals. (C) 2001 Acad
emic Press.