Annual cycle of testicular maturation in the helmet crab Telmessus cheiragonus
Article first published online: 28 NOV 2003
Volume 69, Issue 6, pages 1200–1208, December 2003
How to Cite
NAGAO, J. and MUNEHARA, H. (2003), Annual cycle of testicular maturation in the helmet crab Telmessus cheiragonus. Fisheries Science, 69: 1200–1208. doi: 10.1111/j.0919-9268.2003.00746.x
- Issue published online: 28 NOV 2003
- Article first published online: 28 NOV 2003
- Received 18 April 2003. Accepted 6 August 2003.
- helmet crab;
- mating season;
- reproductive cycle;
- Telmessus cheiragonus;
- testicular maturation
ABSTRACT: To clarify the annual testicular maturation cycle in the helmet crab Telmessus cheiragonus, seasonal histological changes of the testis and occurrence of grasping pairs and recently copulated females with fresh sperm plugs were investigated. The testis was composed of seminiferous ducts with many testicular lobules. Development of the lobules was divided into six stages (spermatogonia proliferation, first spermatocyte, reduction division, spermatid, spermiogenesis and free sperm stage) based on the spermatogenic phase of the germ cells in each lobule. The mean percentage of the lobules during each stage was calculated every 1–3 months. Developed lobules occurred with a high percentage throughout the year except in June when developing lobules predominated. Grasping pairs and females with fresh sperm plugs were collected during April–July with a peak in May–June. These results suggest that the males have testis with many developing lobules in June when they are active for mating. Newly formed spermatozoa may be stored in the testis and the vas deferens until the next mating season after June, as the spermatozoa may not have an opportunity to fertilize eggs until the next season and there is no sign of spermatozoa absorption in the testis.