1990, Bronstein 1998, Heil and McKey 2003). Whereas space is rarely a limiting factor

for terrestrial ant communities (Albrecht and Gotelli 2001), ants inhabiting

myrmecophytes may face strong inter- and intra-specific competition for limited nest

sites (Janzen 1966, Davidson et al. 1989, Fonseca and Ganade 1996, Fonseca 1999,

Stanton et al. 2002). Therefore, although young myrmecophytes may experience

multiple colonization events by queens of different species or undergo a succession of ant

species as they plant grow, mature plants are usually dominated by a single ant colony

(Davidson et al. 1989, Longino 1991, Vasconcelos 1993, Young et al. 1997, Palmer et al.

2000, Feldhaar et al. 2003).

 Recent studies on ant-plant relationships have provided empirical models for both

spatial (e.g., Yu et al. 2001, Palmer 2003) and temporal (e.g., Young et al. 1997, Alonso

1998) habitat partitioning among ant species that inhabit the same plant species. In some

systems, variation in host-plant characteristics, often related to underlying habitat

heterogeneity, allows fine-scale partitioning of resources among ant species (Davidson et

al. 1989, Longino 1989, Vasconcelos and Davidson 2000, Palmer 2003). In more

homogeneous conditions, coexistence may result from interspecific differences in ant life

histories and behaviors, including trade-offs between competitive dominance and

dispersal capability (Stanton et al. 2002), fecundity and dispersal ability (Cole 1983,

Vasconcelos 1993, Yu and Wilson 2001, Yu et al. 2004), or interference and exploitation

competition (Fellers 1987, Davidson 1998, Holway 1999). Positive priority effects (the

continued occupation of the species that colonizes first) may also allow ant species that

are poor competitors or even poor colonizers to occupy sites following colony