rate of colony founding for the few queens produced, as Cole (1983) suggested for other

species of Pseudomyrmex and Cephalotes (= Zacryptocerus) that inhabit mangrove

islands. Positive priority effects for young colonies of these subdominant species,

namely the ability to resist eviction by the larger colonies of A. pittieri or Cr. carinata

following colony establishment, may explain this phenomenon. Workers of both C.

setulifer and P. fortis are much larger than those of A. pittieri and Cr. carinata, which

could result in favorable one-on-one success in conflict for the former two species, or at

least for the aggressive P. fortis (McGlynn 2000). Both ant species also have

formidable, though very different, defenses: queens and major workers of Ce. setulifer

effectively block the entrances to their domatia with their phragmotic heads, and P. fortis

workers possess a powerful sting. Colony size alone has proven to be a strong predictor

of competitive outcome in other ant communities (Fellers 1987, Palmer 2004), but, as

shown in this and other systems, morphological and behavioral adaptations of ant species

are also important in determining the outcome of competitive interactions (Davidson

1998, Holway 1999).

 In order to understand the effects of microhabitat occupation and ant competition

in the context of the mutualism, it is useful to explicitly consider the life history of the

plant that provides the resources for which the ant species presumably compete

(Bronstein 1998, Heil and McKey 2003). If one or more of the ant species provide

fitness benefits for C. alliodora individuals, then selection on plant life history traits

would favor allocation for ant-related traits (i.e., domatia production and lack of chemical

defenses against ant-tended coccoids) at the stage where acquiring a protective ant colony

is most beneficial and least costly (Brouat and McKey 2000). Because the ant species