Growth of populations and the fungus garden of Atta sexdens rubropilosa (Hymenoptera, Formicidae) response to foraged substrates

Abstract

The leaf-cutting ants forage diverse plants for cultivation of symbiotic fungus, which is a primary food source for larvae in the colony. Previous studies have suggested that continuous offering of a single vegetal species affects the preference of workers and colonial performance (growth of the population and fungus garden). Given this situation, we evaluated the preference of workers and the performance of a colony of Atta sexdens rubropilosa after continuously offering the same plants for 2 months. The foraging behavior of workers exhibited a polyphagia typical of leaf-cutting ant species that collect all the vegetal species. The fungus gardens exhibited inequality in the production of staphylae, according to the substrate offered. This was directly reflected in population growth, queen weight and oviposition rate. We also noted that selection of plants is not correlated with the plant substrate that promotes good development of symbiotic fungus, but rather with the individual decisions taken by workers. Such results demonstrate the importance of plant diversity for fungus garden maintenance and subsequent population and fungus growth.