TERRITORY DEFENSE BY THE ANT AZTECA-TRIGONA - MAINTENANCE OF AN ARBOREAL ANT MOSAIC

Mosaics of exclusive foraging territories, produced by intra- and inte rspecific competition, are commonly reported from arboreal ant communi ties throughout the tropics and appear to represent a recurring featur e of community organization. This paper documents an ant mosaic within mangrove forests of Panama and examines the behavioral mechanisms by which one of the common species, Azteca trigona, maintains its territo ries. Most of the mangrove canopy is occupied by mutually exclusive te rritories of the ants A. trigona, A. velox, A. instabilis, and Cremato gaster brevispinosa. When foraging workers of A. trigona detect worker s of these territorial species, they organize an alarm recruitment res ponse using pheromonal and tactile displays. Nestmates are attracted o ver short distances by an alarm pheromone originating in the pygidial gland and over longer distances by a trail pheromone produced by the P avan's gland. Recruits are simultaneously alerted by a tactile display . No evidence was found for chemical marking of the territory. Major w orkers are proportionally more abundant at territory borders than on f oraging trails in the interior of the colony. The mechanisms of territ ory defense in A. trigona are remarkably similar to those of ecologica lly analogous ants in the Old World tropics.