Anatomy and fine structure of the metapleural gland in Atta (Hymenoptera, Formicidae).

Representatives of the ant genus Atta Fabricius possess metapleural glands that are characterized by a complex morphological organization. In contrast to most other glands in these ants a muscular supply nearby the glandular orifice is lacking. An hypothesis is postulated concerning the implication of the morphology of the glandular opening for the release of the secretion, probably facilitated by the existence of a cuticular ridge between the glandular opening and the hindlegs. In three species (Atta bisphaerica, Atta laevigata and Atta sexdens) the ultrastructure of the gland was studied. The elongated secretory cells possess a fairly developed granular endoplasmic reticulum. Very often we observed the presence of inclusions of lysosomal origin.