Mendonça M T, Crews D
Institute of Reproductive Biology Department of Zoology, University of Texas at Austin, 78712, USA.
J Comp Physiol A. 1996;178(3):373-81. doi: 10.1007/BF00193975.
Activation of courtship behavior in male red-sided garter snakes, Thamnophis sirtalis parietalis, is independent of the presence of sex steroids. The only consistent treatment that stimulates courtship behavior in males is prolonged exposure to low temperature followed by subsequent warming, mimicking the emergence from hibernation. We investigated whether attractivity and receptivity in female red-sided garter snakes is similarly steriod independent. Female red-sided garter snakes are attractive when they emerge from hibernation and are courted by males; most mate within an hour of emergence. In a series of experiments, groups of females were either ovariectomized (OVEX) in the late spring, fall or while in hibernation. They were tested for attractivity and receptivity upon emergence from hibernation. Females OVEX in the spring were unattractive whereas those OVEX in fall or while in hibernation were attractive. Thus, attractivity appears determined the year before emergence and is dependent on the presence of the ovaries. All OVEX females were unreceptive upon emergence. OVEX females were also given replacement estradiol (E) treatment (either in Silastic capsules or single injections) at various points of their annual cycle. The only treatment that resulted in reinstating receptivity in OVEX females was the injection of E (20 micrograms) one hour prior to emergence. The effectiveness of E in reinstating receptivity was time dependent: the longer the period between emergence and injection, the less effective the same dosage was in stimulating receptive behavior. These experiments suggest that sexual behavior in female red-sided garter snakes is, unlike males, dependent on the presence sex steroid hormones. Although E is naturally at its lowest seasonal level upon emergence, the concentration is sufficient to stimulate receptivity. However, it appears that temperature regulates a time-limited window of sensitivity to E.
雄性红侧带蛇（学名：Thamnophis sirtalis parietalis）求偶行为的激活与性类固醇的存在无关。唯一能 consistently 刺激雄性求偶行为的处理方式是长时间暴露于低温环境，随后升温，模拟从冬眠中苏醒的过程。我们研究了雌性红侧带蛇的吸引力和接受度是否同样与类固醇无关。雌性红侧带蛇从冬眠中苏醒时具有吸引力，会受到雄性的求偶；大多数在苏醒后一小时内交配。在一系列实验中，将雌性蛇分为几组，分别在晚春、秋季或冬眠时进行卵巢切除（OVEX）。在它们从冬眠中苏醒后，测试其吸引力和接受度。春季进行卵巢切除的雌性没有吸引力，而秋季或冬眠时进行卵巢切除的雌性则具有吸引力。因此，吸引力似乎在出蛰前一年就已确定，并且取决于卵巢的存在。所有接受卵巢切除的雌性在苏醒时都不接受交配。还在接受卵巢切除的雌性蛇的年度周期的不同时间点给予它们雌二醇（E）替代治疗（要么通过硅胶胶囊，要么单次注射）。唯一能使接受卵巢切除的雌性恢复接受度的治疗方法是在苏醒前一小时注射 E（20 微克）。E 在恢复接受度方面的有效性与时间有关：出蛰与注射之间的时间间隔越长，相同剂量在刺激接受行为方面的效果就越差。这些实验表明，雌性红侧带蛇的性行为与雄性不同，依赖于性类固醇激素的存在。尽管出蛰时 E 的自然季节性水平最低，但该浓度足以刺激接受度。然而，似乎温度调节了对 E 的敏感性的时间限制窗口。
