Morphology and Ultrastructure of the Dufours and Venom Gland in the Ant Myrmecia-Gulosa (Fabr) (Hymenoptera, Formicidae)

Abstract

The morphology and fine structure of the two major sting glands in the primitive Australian bull ant, Myrmecra gulosa, are described. The cells of the glandular epithelium of the tubiform Dufour's gland are characterised by a well developed vesicular smooth endoplasmic reticulum, numerous lamellar inclusions, and microvillar differentiations of the apical cell membrane. The cells of the secretory filaments of the venom gland contain a very extensive granular endoplasmic reticulum and numerous Golgi vesicles. The highly proteinaceous secretion reaches the filament lumen through the intracellular end apparatus. Passage through the convoluted gland probably accompanies the modification or production of additional secretory components, as is suggested by the ultrastructural organisation of the convoluted gland cells. The large venom gland reservoir is lined with squamous epithelial cells and a thick cuticular layer, that protects the ant from self-toxication by the powerful venom. Each sting gland opens separately through the sting, and possesses its own muscular control mechanism that allows independent discharge of secretion.