Mandibles of leaf-cutng ants: Morphology related to food preference

Abstract

Feeding adaptaton is crucial for the ecological success of animals, which explore specific or varied resources according to the suitability of the selected morphological feature. We hypothesized that the mandibles of leaf-cutng ants exhibit a specializaton because of the specific food preference of some species. The objectve of this study was to highlight possible morphological differences between the mandibles of leaf-cutng ant species of the genus Ata related to food preference, i.e., to investgate the morphofunctonality. A detailed descripton of the mandibles of workers of the grass-cutng ant Ata bisphaerica and of the leaf-cutng ant Ata sexdens rubropilosa was provided. For morphometric analysis, 50 individuals of four size classes were dissected for removal of the right mandible and one sample of each caste was processed for scanning electron microscopy. It was observed differences between species and among castes, demonstratng the clear specializaton of workers. Although the results of mandibular morphometry accept the hypothesis of morphofunctonality, further investgaton is needed taking into consideraton the body size of foragers, robustness and factors that confer greater resistance to the mandibles such as zinc content, the force employed during cutng, and mandibular biomechanics.