Preliminary observations on spermatogenesis in immature stages and fertile and sterile castes of Kalotermes flavicollis (Fabr.) (Isoptera: Kalotermitidae)

Testes of larvae, nymphs, primary reproductives, pseudergates and soldiers of K. flavicollis were investigated with light and electron microscope. In the course of male gonad morphogenesis, at the apex of the testis lobes an apical tissue differentiates and persists even in the imago. In larvae, up to 4th instar, the lobes are made up of morphologically similar cells in which a distinction between somatic and germ cells is not possible. During transition from 4th to 5th larval instar, the lobes acquire the typical structure of the follicle testes of insects. In primary reproductives, the testes are voluminous and all four regions with peculiar patterns of germ cells differentiation increase their size. In pseudergates, nymphs and soldiers, although the stages of spermatogenesis and spermiogenesis are found, testes do not reach the size, structure and fully functional state of primary reproductives.