Sperm storage in turtles: A male perspective.

The storage and behavior of sperm collected from the epididymis of two emyiid turtles were examined. In Chrysemys picta, the weight of the epididymis does not change significantly throughout the year as does the testis. However, in this species, as well as in Trachemys scripta, the epididymis contains sperm throughout the entire year. Sperm from both species have a relatively low motility and velocity of movement. In C. picta, equally low motilities are observed both in the autumn, shortly after spermiation, and in spring. Motility could be augmented by the addition of isobutyl methyl xanthine (IBMX, 0.5 mmol l(-1)). Epididymal sperm remained viable in excess of 40 days in vitro when stored in F-10 buffer, during which time motility and swimming velocity could be augmented with IBMX. The longevity and low motility of turtle sperm facilitates its storage by either males or females, and creates conditions that promote the wide dissemination, over time, of gametes produced in a narrow time window.