Seasonally breeding mammals display timely physiological switches between reproductive activity and sexual rest, which ensure synchronisation of births at the most favourable time of the year. These switches correlate with seasonal changes along the hypothalamo-pituitary–gonadal axis, but they are primarily orchestrated at the hypothalamic level through environmental control of KISS1-dependent GnRH release. Our field study shows that births of fossorial water voles, Arvicola terrestris, are concentrated between March and October, which indicates the existence of an annual reproductive cycle in this species. Monthly field monitoring for over a year further reveals dramatic seasonal changes in the morphology of the ovary, uterus and lateral scent glands, which correlate with the reproductive status. Finally, we demonstrate seasonal variation in kisspeptin expression within the hypothalamic arcuate nucleus. Altogether, this study demonstrates a marked rhythm of seasonal breeding in the water vole and we speculate that this is governed by seasonal changes in photoperiod.

季节性繁殖的哺乳动物在生殖活动和性休息之间表现出及时的生理转换，从而确保在一年中最有利的时间同步分娩。这些开关与沿下丘脑-垂体-性腺轴的季节性变化相关，但它们主要通过对 KISS1 依赖性 GnRH 释放的环境控制在下丘脑水平进行协调。我们的实地研究表明，化石水田鼠Arvicola terrestris的出生, 集中在 3 月和 10 月之间，这表明该物种存在年度繁殖周期。一年多的月度现场监测进一步揭示了卵巢、子宫和侧向气味腺形态的显着季节性变化，这与生殖状态相关。最后，我们展示了下丘脑弓状核内kisspeptin 表达的季节性变化。总而言之，这项研究证明了水田鼠季节性繁殖的明显节奏，我们推测这是由光周期的季节性变化控制的。