Spermiogenesis in boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae)

Abstract Spermiogenesis of Anthonomus grandis Boheman, the cotton boll weevil, was studied by transmission electron microscopy. The basic morphologic features investigated and illustrated were: acrosome, nucleus, fibrous masses, microtubules, and mitochondrial derivatives. A centriole adjunct was observed to surround the basal body (centriole derivative) early in spermiogenesis, but it subsequently disappeared. In the sperm tail, one mitochondrial derivative developed into a rod-like structure that inserted into a concavity at the base of the nucleus and terminated near the end of the tail. This mitochondrial derivative may provide a rigid base for the undulating membrane. In addition, the attachment of the rod to the nucleus may serve in a manner analogous to the function that has been suggested for the centriole adjunct: it may anchor the head to the tail. A possible abnormal condition may arise when the mitochondrial derivative rod fails to insert into the sperm nucleus.