Does Atta laevigata (Smith, 1858) act as Solanum lycocarpum seed dispersers?

Abstract

Ants can act as seed dispersers, modifying their distribution, affecting the reproductive success and the vegetation spatial structure. The leaf-cutting ants function, as dispersers of non-myrmecochorous plants, is little known. This work aimed to evaluate descriptively the Atta laevigata interaction with Solanum lycocarpum diaspores. The observations were carried out, throughout 10 days, in a secondary fragment of Semidecidual Seasonal Forest in Ivinhema, MS. To determine the removal rate, 500 seeds were taken from ripe fruits, dried, labeled and distributed in groups ranged from five to 50 seeds, totaling 100 seeds per foraging trail. Groups of 30 seeds with pulp were also distributed every 1.0 m on the trails. Individuals of different sizes presented different interactions to the fruits and seeds, smaller workers carried pulp or seeds separately, medium workers carried seeds with pulp or cleaned them before carry to the nest and the largest workers carried the seeds to the nest. Atta laevigata acted primarily as predators, with few seeds discarded. Their actions may interfere in the native vegetation regeneration, with a significant role in removing S. lycocarpum seeds, a pioneer species, and in population control for this species by the severe predation of seeds. However, the remaining1.6% intact seeds allows germination, with the A. laevigata acting as a seed dispersers over short distances for this species, favoring the S. lycocarpum dispersion.