Temperature as an important factor determining ant dominance

Abstract

Ant dominance, or the monopolization of food resources by these insects, is widely studied among ecologists and, sometimes, considered as an important factor for the understanding of biological communities. However, even though ant dominance receives a great importance in community ecology discussions, there is no consensus about what could cause its occurrence: conditions, resources, biological interactions, or a combination of these. Therefore, the aim of this work was to evaluate the influence of elevation in ant dominance. Moreover, we evaluated if temperature, leaf litter depth, and dry mass of ground dwelling invertebrates can influence the occurrence of ant dominance. To verify this, we collected our data at the elevational gradient of Parque Nacional do Itatiaia, as the variables we tested are subject to the variation of elevation. The samples were collected at seven elevations (700, 800, 1100, 1500, 1800, 2200, and 2400 m a.n.m), always in forest habitats, and for each of them we baited sardine and honey to ants. The mean annual temperature for each elevation was obtained from WorldClim dataset (version 1.4), and leaf litter depth and ground dwelling invertebrates were collect at the same points where baits were offered. The occurrence of ant dominance decreased with the increase of elevation, but this response was not related to the bait type. Only temperature had a relationship with the elevational gradient, which was negative. However, neither leaf litter depth, or dry mass of invertebrates were related to elevaiton. Finally, temperature was positively related to the occurrence of dominance. This work showed how ant dominance responds to an extensive elevational gradient. Besides, we showed that temperature, a condition, was the only variable among the tested ones that was related to ant dominance. This is an important step to the understanding of ant dominance, and how would dominance be related to aspects of community ecology.