Structure and developmental changes in the tergal glands of adult females of Coptotermes formosanus (Isoptera, Rhinotermitidae)

Abstract

Female alates of the Formosan subterranean termite Coptotermes formosanus, possess a pair of glands under the 9th and 10th abdominal tergites. These tergal glands located just below the cuticle have two distinct regions. The outer part is made up of type 1 cells. These cells possess large nuclei, abundant mitochondria and bundles of microtubules. Apically the cells possess a distinct layer of microvilli. Numerous ducts with thick cuticular walls are seen traversing this region and the cuticle. The basal two thirds of the gland is composed of glandular cells which in the post-swarming female are packed with electron dense granules closely associated with mitochondria. The basement membrane has several conspicuous invaginations giving the gland a segmented appearance. In newly molted females, the glandular area lacks the dense granules but instead has electron lucent granules. Following swarming the alates lose their wings, a male and a female form a nuptial chamber, mate and lay eggs. In 7–10 day old females, the dense granules coalesce forming larger granules that appear to move towards the area of the intersegmental membrane for possible release. Also the cells appear to degenerate and large number of vacuoles appear throughout the gland.