Studies on the reproductive system of Hymenolepis diminuta using autoradiography and transplantation.

Adult Hymenolepis diminuta exposed in vitro for 3 hr to 3H-thymidine showed incorporation of the isotope on autoradiograms over nuclei of actively dividing cells in the testes, ovary, vitellaria, and developing embryos in the eggs. Timing studies utilizing labeled worms transplanted to uninfected hosts showed that it took 18 hr for spermatogonia to develop to primary spermatocytes, 24 hr to secondary spermatocytes, 36 hr to spermatids, and 48 hr to sperm bundles. Self-insemination was confirmed in single worm transplants of 3 days by the presence of labeled sperm in the seminal receptacles. In multiple worm transplants labeled worms inseminated themselves in each case and cross-inseminated with 92% of the unlabeled worms present.