Structural and chemical ontogeny of the postpharyngeal gland in the desert ant Cataglyphis niger

The postpharyngeal gland of Cataglyphis niger (Andre, 1881) workers is characterized, at the ultrastructural level, by a well-developed smooth endoplasmic reticulum, Golgi apparatus, and numerous mitochondria and lamellar inclusions suggesting an involvement in Lipid metabolism. In addition, the microvillar differentiation of the apical membrane and basal invaginations of the cell imply a transportation process. The gland shows a clear structural as well as chemical age-dependent development. Epithelial thickness increases with age, reaching its maximum within the first week after emergence. Concurrently there is a progressive development of microvilli and appearance of the lamellar inclusions. The gland's secretion consists mainly of hydrocarbons, with a predominance of monomethyl and dimethyl alkanes. Congruency was found between the hydrocarbon composition of glandular exudates and those of the epicuticular washes. An age-dependent increase in the total amount of hydrocarbons was found to correlate with the ultrastructural development and gross morphology (thickness of epicuticular lining) of the gland.