Publication Date

12-1982

Advisor(s) - Committee Chair

Blaine Ferrell, Hugh Puckett, Joe Winstead

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Interrupted-night photoperiod experiments were carried out in green anoles (Anolis carolinensis) in July and August 1981 in order to explore the possibility that seasonal timing of testicular regression regulated by day length involves circadian rhythms. The influence that temperature has on testicular responsiveness to light was also assessed. Testicular weight responses to different interrupted-night photoperiod treatments were similar in anoles kept at constant warm temperatures but varied in anoles kept at constant cold temperatures. Rates of decline of spermatogenesis in response to different interrupted-night photoperiod treatments were, on the other hand, similar in anoles kept at constant cold temperatures but varied in anoles kept at constant warm temperatures. Testicular regression occurred at a faster rate in anoles held in environmental chambers set at constant warm temperatures or at a thermocycle of warmcold temperatures compared with the rate in anoles kept at constant cold temperatures or at a thermocycle of cold-warm temperatures regardless of photoperiodic conditions. Results of this study support the concept that the mechanism whereby day length influences the timing of testicular regression does involve circadian rhythms. The results further indicate that the temperature experienced, particularly during day light hours, can modify the influence of day length on the timing of testicular regression.

Disciplines

Biology | Life Sciences

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