AJP - Regulatory, Integrative and Comparative Physiology, Vol 257, Issue 6 1548-R1550, Copyright © 1989 by American Physiological Society
Effect of fall mating on ovarian development in the red-sided garter snake
M. T. Mendonca and D. Crews
Institute of Reproductive Biology, University of Texas, Austin 78712.
Although spring mating is an important factor in initiating vitellogenesis
in female red-sided garter snakes (Thamnophis sirtalis parietalis), some
females can become vitellogenic without having mated in the spring. Two
hypotheses have been proposed to explain this phenomenon: 1) long-term
storage of copulatory stimuli from mating the previous fall, or 2)
additional cue(s) overcoming the lack of mating to stimulate
vitellogenesis. Through oviductal biopsy, the presence of sperm in females
returning to the hibernaculum in the fall was assessed. Laparotomies
performed just before and 6 wk after hibernation indicated that although
fall mating may stimulate slight ovarian development in the fall, there
appears to be no effect of fall mating on spring ovarian recrudescence.
Spring mating seems to be the most important factor in determining ovarian
maturation. Therefore, it appears that there is no long-term storage of
copulatory cues and that other as yet unknown cues are responsible for
initiating vitellogenesis in spring unmated females.
