ANT WARS - COMBAT STRATEGIES, TERRITORY AND NEST DEFENSE IN THE LEAF-CUTTING-ANT, ATTA-LAEVIGATA

Two laws have been highlighted when discussing combat strategies in an ts: the linear law (in a series of one-to-one conflicts, a few good fi ghters are better than many poor fighters) and the square law (if all individuals are vulnerable to attack, numerous fighters are more advan tageous than a few good fighters). The leaf-cutting ant, Atta laevigat a, responded to a simulated vertebrate threat by recruiting many soldi ers (large workers), but responded to conspecific and interspecific an t threats by recruiting mainly small ants. In staged intraspecific int eractions in the field between adjacent nests, ants were reluctant to fight on unmarked land and often retreated onto established marked tra ils, retreated to the nest entrance which they then capped or guarded, or immediately began marking the battle site with Dufour's gland secr etion. These results indicate that the territorial behaviour of A. lae vigata is part of a complex system to defend resources, where the defe nce of one resource (food) can develop into the defence of another (th e nest). During the build-up of a war, once individuals from two nests met, recruitment changed from medium and large ants to mainly small a nts. II is suggested that A. laevigata uses the soldier caste to defen d the nest against large organisms and recruits numerous small ants in response to conspecific and interspecific ant threats following the s quare law. (C) 1996 The Association for the Study of Animal Behaviour