Oviductal sperm storage as a reproductive tactic of turtles

Abstract

The oviducts of two species of freshwater turtles were examined throughout the year to determine the distribution of sperm within the oviduct, the locations of stored sperm, and the onset of mating. Sperm were stored in undifferentiated tubules and ducts of submucosal glands at the periphery of large glandular segments of the albumen and uterine regions of the oviduct. Sperm transfer to females commenced in October in Sternotherus odoratus and in January in Trachemys scripta. The role of sperm storage in the annual reproductive cycle of freshwater turtles is evaluated in light of the onset of sperm transfer to females and the timing of ovulation and oviposition. Stored sperm are most likely to be utilized in the fertilization of eggs ovulated in the second and subsequent egg clutches.

Female reproductive qualities affect male painted turtle (Chrysemys picta marginata) reproductive success

“…Any source of variation in female reproductive quality has the potential to increase the importance of female qualities to male RS. Reproductive frequency is one of the largest contributors to variation in reproductive output of female turtles (Gibbons 1982;Congdon et al 2003), and a major function of stored sperm is to fertilize within-season clutches (Gist and Congdon 1998;McGuire et al 2011). Therefore, we predict that female quality will have the greatest influence on male RS in turtle species that produce multiple within-season clutches compared to species that produce a maximum of one clutch per season.…”

“…In addition, female painted turtles can apparently store viable sperm for long durations (Gist and Jones 1989;Gist et al 2002). Gist and Congdon (1998) predicted that fertilizing sequential within-season clutches would be a primary function of stored sperm due to the narrow window of time between oviposition and ovulation of second-clutch follicles of turtles. That prediction was supported for painted turtles that use stored sperm to fertilize the majority (>95 %) of clutches produced within a season and paired clutches of some individuals among years Pearse et al , 2002McGuire et al 2011).…”

Mating system, multiple paternity and effective population size in the endemic flatback turtle (Natator depressus) in Australia

“…However, there may be selective pressures on both males and females to mate multiply in a scramble mating system (Jessop et al 1999) due to the energetic costs of travelling to and staying at courtship areas that are sometimes distant from nesting beaches (courtship areas are not observed off Peak Island or Mon Repos). Regardless of the actual timing of matings among the female flatback turtles studied, the observed shifts in paternal success indicate dynamic processes within the sperm storage tubules and ducts of the upper oviduct, as shown for freshwater turtles (Gist and Jones 1989;Gist and Congdon 1998) indicative of sperm storage and the potential for sperm competition. Whether multiple paternity in turtles results in greater fitness for females is unknown but in one study extensive enough to address this question, mean hatching success was not significantly higher for C. picta clutches with multiple paternity .…”

Sperm storage and morphofunctional bases of the female reproductive tract of the snake Philodryas patagoniensis from southeastern Brazil

“…We also compare the anatomy of the female reproductive tract of P. patagoniensis and propose an adjustment in the nomenclature for oviductal portions of snakes including the use of the term utero-vaginal junction (UVJ). This term has already been used for lizards (Sever and Hamlett 2002), birds (Bakst 1987), and turtles (Gist and Congdon 1998).…”