Chen Yan, Wang Dawei, Li Ning, Hu Xiangfa, Ren Fei, Hao Weili, Song Ying, Liu Xiaohui
State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
College of Life Sciences, Sichuan University, Chengdu, China.
Integr Zool. 2019 Sep;14(5):435-445. doi: 10.1111/1749-4877.12330.
Age structure and seasonality influence the population fluctuations of small rodents. Age determines body weight and social experience, while seasonality regulates the duration of the breeding season and onset of sexual maturity in newborn offspring. Therefore, reproductive success and skew usually occur in different age groups. Brandt's vole (Lasiopodomys brandtii) is a social, short-lived and seasonal breeding small rodent with a dramatic seasonal population fluctuation, but reproductive skew is not fully understood in this species. In the present study, we determined kinship in semi-natural enclosure populations using microsatellite markers based on genotyping, analyzed the reproductive skew between sexes and between overwintered and newborn voles, and monitored variation in male reproductive activity by testing fecal testosterone levels throughout the year. Overwintered voles had the most reproductive success along with a striking increase in the population size in the enclosures, with all biological fathers and 77.8% of biological mothers, which had 100% and 87% of the total offspring, respectively. Compared to overwintered voles, reproductive skews were significantly higher in potential overwintered and newborn parents, implying the possible reproductive suppression of newborn voles by dominant overwintered voles. Moreover, both heavier body weight and higher testosterone levels in overwintered males supported their potential social status in the population. Our study provided new evidence for reproductive skew and differentiation of postnatal gonadal development patterns of different age groups in Brandt's vole.
年龄结构和季节性会影响小型啮齿动物的种群波动。年龄决定体重和社会经验，而季节性则调节繁殖季节的时长以及新生后代性成熟的起始时间。因此，繁殖成功率和偏斜通常发生在不同年龄组中。布氏田鼠（Lasiopodomys brandtii）是一种群居、寿命短且季节性繁殖的小型啮齿动物，其种群数量存在显著的季节性波动，但该物种的繁殖偏斜尚未完全被了解。在本研究中，我们基于基因分型使用微卫星标记确定了半自然围栏种群中的亲缘关系，分析了性别之间以及越冬田鼠和新生田鼠之间的繁殖偏斜，并通过全年检测粪便睾酮水平来监测雄性繁殖活动的变化。越冬田鼠繁殖成功率最高，同时围栏内种群数量显著增加，所有生父以及77.8%的生母分别拥有总后代的100%和87%。与越冬田鼠相比，潜在越冬田鼠和新生田鼠父母的繁殖偏斜显著更高，这意味着优势越冬田鼠可能对新生田鼠存在繁殖抑制。此外，越冬雄性田鼠体重更重且睾酮水平更高，这支持了它们在种群中的潜在社会地位。我们的研究为布氏田鼠不同年龄组的繁殖偏斜和出生后性腺发育模式的分化提供了新证据。
