Assembléias de formigas do Parque Estadual do Itacolomi (MG) e relações intra e interespecíficas entre espécies dominantes

Abstract

Arboreal ants usually show a strong territolialist behavior, defending aggressively their foraging sites or the area surrounding their nest against individuals of other colonies. Thereby, the most aggressive ants with larger distribution, which may be considered dominants, defines the ant assemblage structure by shaping species distributions into threedimensional mosaics in the forest canopies. The objective of the work was to investigate the indicative of the mosaic existence through the distribution, richness and abundance of ants in three different successional stages of a montane tropical forests. In oerder to obtain a more detailed investigation about dominant species, and so identify mosaic building mechanisms, the aggressiveness degree and dominance of Camponotus (Myrmothrix) rufipes (Fabricius), a dominant species in Parque Estadual do Itacolomi was evaluated through experiments in field and in laboratory. Later, it was also evaluated this species behavior in the face of a potential competitor, Camponotus (Myrmepomis) sericeiventris (Guérin – Menéville), which has a similar body size, eats the same types of food and uses the same nesting sites. Species richness and abundance were significantly higher in the soil than in the canopy and understorey, regardless successional stage. On the other hand, those parameters did not vary significantly between the successional stages, although species composition did, thus suggesting that there are typical species for each successional stage. The species considered dominant were Camponotus rufipes and Myrmelachista sp.1. Concerning the field experiments and laboratory, it was observed that the species C. rufipes and C. sericeiventris presented many aggressive exhibitions in their behavioral repertoire, being able to drive away other ants. However, they seem to be tolerant of many other species that can coexist in smaller densities, with different body sizes and even using different foraging strategies. xvii Camponotus sericeiventris showed indications about the capacity of excluding C. rufipes from their forage area.