Dear Enemy Phenomenon in the leaf-cutting ant Acromyrmex lobicornis: behavioral and genetic evidence

DIMARCO, ROMINA; FARJI-BRENER, ALEJANDRO GUSTAVO; PREMOLI, ANDREA

BEHAVIORAL ECOLOGY

OXFORD UNIV PRESS INC

Lugar: Oxford; Año: 2010 vol. 21 p. 304 - 310

1045-2249

The defense of territory through aggressive behavior is well known in animals. However, some territorial animal species respond less aggressively to intrusions by their neighbors than to intrusions by non-neighbors to minimize the costs of continuous fights, a phenomenon termed the dear enemy phenomenon (DEP). Although several studies show the existence of this phenomenon, little is known about the mechanism behind it. One of the possible mechanisms that could explain this behavior is the degree of genetic divergence between neighbors compared with non-neighbors. We tested the DEP hypothesis and whether genetic divergence among nests might drive the DEP in the leaf-cutting ant Acromyrmex lobicornis in Patagonia, Argentina, through behavioral and genetic studies. Individuals from nearby colonies interacted less aggressively than individuals from distant colonies. However, levels of genetic divergence between nearby and between distant nests were similar. Our results support the dear enemy hypothesis, but suggest that the difference in aggressive behavior does not have a genetic explanation. Other possible causes of this behavior, such as habituation, are discussed.