A new exception to the dominance-discovery trade-off rule in ant communities

Interspecific competition is one of the main factor shaping ant community structure. The "dominance-discovery trade-off", an inverse relationship between interference and exploitative competitive ability, is thought to be a fundamental mechanism facilitating coexistence of ants. Despite its widely acceptance in literature, this trade-off appears to be broken in several cases and needs further investigations. Thus, the aim of the present study was to detect the presence/absence of the dominance-discovery trade-off in Mediterranean ant communities. Samplings were conducted inside the Presidential Estate of Castelporziano (Rome, Italy) and seven sampling sites were selected according to their vegetation structure. In each site, baiting was conducted to assess two behavioural indices for each species: the monopolization index and the discovery ability index. Correlation analyses showed no evidence for the existence of a dominance-discovery trade-off. Furthermore, a positive correlation between the two indices was detected in some of the sampling sites. The dominance-discovery trade-off seems therefore to be just one of the possible mechanisms facilitating species coexistence in ant communities