Department of Life Sciences, Academic College Achva, M.P. Shikmim, Israel.
Gen Comp Endocrinol. 2012 Nov 1;179(2):241-7. doi: 10.1016/j.ygcen.2012.08.021. Epub 2012 Sep 4.
The Saharan sand viper, Cerastes vipera (Linnaeus, 1758), is distributed in all Saharan countries, being confined to sand and dune systems. This relatively small snake, up to 35 cm, is nocturnal, is active from spring to autumn (April to October) and hibernates during the winter (November to March). We predicted that C. vipera would have peak plasma testosterone concentration at mating and that the vas deferens would contain abundant spermatozoa at that time. To test our predictions, we collected information on the time of mating and measured monthly testosterone concentration, testes size and testicular activity in free-living male C. vipera during its active period from April to October. Mating occurred only during spring. The pattern of plasma testosterone concentration, testes volume, seminiferous tubule diameter and spermatogenesis all followed the general pattern of high values in autumn and spring and low values in early summer. Our predictions were partially supported. There was a high plasma testosterone concentration at mating in spring and the vas deferens contained abundant spermatozoa, as predicted, but there was also a high plasma testosterone concentration in autumn without mating. We concluded that: (1) males are both aestival in that they produce spermatozoa in autumn, which they store over the winter hibernation period, and vernal in that they produce spermatozoa in spring prior to mating; (2) matings are associated with spermatogenesis; and (3) the high plasma testosterone concentration is concomitant with both matings and spermatogenesis in spring and with spermatogenesis in autumn. We propose that C. vipera has a single peak of testicular activity and plasma testosterone concentration which start in autumn and end in spring. We also propose that spermatogenesis is prior to spring mating and, consequently, is prenuptial.
撒哈拉沙蝰，Cerastes vipera（Linnaeus，1758），分布于所有撒哈拉国家，局限于沙和沙丘系统。这种相对较小的蛇，可达 35 厘米，是夜行性的，从春季到秋季（4 月至 10 月）活跃，并在冬季（11 月至 3 月）冬眠。我们预测 C.vipera 在交配时会有血浆睾丸酮浓度峰值，并且输精管中会有丰富的精子。为了验证我们的预测，我们收集了关于交配时间的信息，并在 4 月至 10 月的活跃期内每月测量自由生活的雄性 C.vipera 的睾丸酮浓度、睾丸大小和睾丸活动。交配仅发生在春季。血浆睾丸酮浓度、睾丸体积、精小管直径和精子发生的模式都遵循秋季和春季高值、初夏低值的一般模式。我们的预测得到了部分支持。春季交配时血浆睾丸酮浓度高，输精管中含有丰富的精子，正如预测的那样，但秋季没有交配时也有高血浆睾丸酮浓度。我们得出结论：（1）雄性是既是夏眠的，因为它们在秋季产生精子，这些精子在冬季冬眠期间储存起来，又是繁殖期的，因为它们在春季交配前产生精子；（2）交配与精子发生有关；（3）春季交配和精子发生时以及秋季精子发生时，血浆睾丸酮浓度都很高。我们提出 C.vipera 只有一个睾丸活动和血浆睾丸酮浓度高峰，从秋季开始，到春季结束。我们还提出精子发生先于春季交配，因此是婚前的。
