Abstract
Interspecific dominance hierarchies have been widely reported across
animal systems. While some dominant individuals (winners) get to
monopolize resources, during dyadic interactions, they can increase
their relative fitness as compared to subdominant individuals (losers).
In some ant species, dominance hierarchies have been used to explain
species coexistence and community structure. However, it remains unclear
whether or in what contexts dominance hierarchies occur in tropical ant
communities. Furthermore, it can be challenging to infer and quantify
reliable dominance hierarchies from observed interactions. This study
seeks to examine whether arboreal twig-nesting ants competing for
nesting resources in a Mexican coffee agricultural ecosystem are
arranged in a dominance hierarchy. Using network analysis, we quantified
interactions between ten species by measuring the uncertainty and
steepness in the dominance hierarchy. We also assessed the orderliness
of the hierarchy by considering species interactions at the network
level. Based on the Elo-ranking method, we found that the twig-nesting
ant species Myrmelachista mexicana ranked highest in the ranking,
while Pseudomyrmex ejectus was ranked as the lowest in the
hierarchy. We quantified the uncertainty in the dominance hierarchy and
found that the hierarchy was intermediate in its steepness, suggesting
that the probability of higher ranked individuals winning contests
against lower ranked individuals was fairly high. Motif analysis and
significant excess of triads further revealed that the species networks
were largely transitive. This study highlights that some tropical
arboreal ant communities self-organize into dominance hierarchies.