Ant Predation on Intertidal Polychaetes of a SW Atlantic Estuarine Environment.

PALOMO M. G.; MARTINETTO P., ; PEREZ C; IRIBARNE, O.

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Año: 2003 vol. 253 p. 165 - 173

0171-8630

Polychaetes in soft-bottom intertidal habitats of the Mar Chiquita coastal lagoon(38° 00’ S, 57° 30’W, Argentina) are the prey of shorebirds, fishes and crabs. Based on 3 yr of fieldsampling, we observed that the fire ant Solenopsis richteri is another important predator of polychaetes(mostly Laeonereis acuta) during the summer (December to March). Ants use intertidal areasadjacent to terrestrial habitats which have well-developed soils and are characterized by inland vegetation(i.e. pampas grasses), but appear to be excluded from habitats with the burrowing crab Chasmagnathusgranulata. Ants build intertidal galleries perpendicular to the shoreline that are used totransport polychaetes to the nest. The ants attacked the polychaetes in burrows with diameters largerthan their own abdomen. They selected larger polychaete sizes, attacking up to 66% of the polychaetesin the high intertidal. Based on our observations, and given the wide range of this species andrelated fire ants, we believe that this terrestrial-marine interaction between fire ants and polychaetescould be a common phenomenon.