Maternal effects and population regulation: maternal density-induced reproduction suppression impairs offspring capacity in response to immediate environment in root voles Microtus oeconomus
Maternal effects and population regulation: maternal density-induced reproduction suppression impairs offspring capacity in response to immediate environment in root voles Microtus oeconomus
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DOI：
10.1111/1365-2656.12307
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发表时间：
2015-03-01
影响因子：
4.8
通讯作者：
You, Zhi-Bing
中科院分区：
文献类型：
--
作者：
Bian, Jiang-Hui;Du, Shou-Yang;You, Zhi-Bing
1.关于母体效应在母体环境向子代表型转化中起到适应性桥梁的作用，从而影响种群动态的假设，在控制良好的领域中尚未被研究过。本研究以根田鼠为材料，研究了母体密度对子代应力轴、繁殖力和种群动态的影响。为繁殖后代而建立的亲本围栏是这样建立的，即在4个(低密度)围栏中每个性别引入6个成虫，在另外4个(高密度)围栏中每个性别引入30个成虫。2周后开始活体诱捕。在20-30日龄捕获的后代被带到实验室，在实验室条件下饲养直到青春期，然后在亲代种群被移走后，用于在这些围栏中建立后代种群。[更正于2015年1月8日首次在线发布后添加：10-20天已改为20-30天。]来自两个亲本来源的后代被分配到四个围栏中，用于建立亲本群体的两种密度处理中的每一种都有两个(对于母亲非应激的后代，被分配为低密度和高密度，称为HL和HH，对于母亲应激的后代，称为HL和HH，被分配为低密度和高密度)。经过两个季节的反复活体诱捕，测试了粪便皮质酮代谢产物(FCM)水平、后代繁殖特征和种群动态。在母亲密度应激和非密度应激的后代之间，观察到种群大小的不同波动。在第二个诱捕季节开始时，LL组和Lh组的种群对初始密度的响应发生了显着变化，达到了相似的水平。然而，HL和HH组的种群数量保持相对稳定，而HL组的低种群数量一直持续到实验结束。母体密度应激与子代性成熟期FCM升高、生殖抑制和体质量下降相关。FCM升高和繁殖抑制与子代种群密度无关，与子代质量下降相关。这些发现表明，母体应激引起的固有状态改变损害了子代对即时环境的反应能力，这些改变可能是由母体应激系统介导的。HL组的非适应性生殖抑制提示，种群密度是产生延迟密度依赖效应的生态因素之一。
1. The hypothesis that maternal effects act as an adaptive bridge in translating maternal environments into offspring phenotypes, and thereby affecting population dynamics has not been studied in the well-controlled fields. In this study, the effects of maternal population density on offspring stress axis, reproduction and population dynamics were studied in root voles (Microtus oeconomus). Parental enclosures for breeding offspring were established by introducing six adults per sex into each of 4 (low density) and 30 adults per sex into each of another 4 (high density) enclosures. Live-trapping started 2weeks after. Offspring captured at age of 20-30 days were removed to the laboratory, housed under laboratory conditions until puberty, and subsequently used to establish offspring populations in these same enclosures, after parental populations had been removed. [Correction added on 8 January 2015 after first online publication: 10-20 days' has been changed to 20-30 days.'] Offspring from each of the two parental sources were assigned into four enclosures with two for each of the two density treatments used in establishing parental populations (referred to as LL and LH for maternally unstressed offspring, assigned in low and highdensity, and HL and HH for maternally stressed offspring, assigned in low and high density). Faecal corticosterone metabolites (FCM) levels, offspring reproduction traits and population dynamics were tested following repeated live-trapping over two seasons. Differential fluctuations in population size were observed between maternally density-stressed and density-unstressed offspring. Populations in LL and LH groups changed significantly in responding to initial density and reached the similar levels at beginning of the second trapping season. Populations in HL and HH groups, however, were remained relatively steady, and in HL group, the low population size was sustained until end of experiment. Maternal density stress was associated with FCM elevations, reproduction suppression and body mass decrease at sexual maturity in offspring. The FCM elevations and reproduction suppression were independent of offspring population density and correlated with decreased offspring quality. These findings indicate that intrinsic state alterations induced by maternal stress impair offspring capacity in response to immediate environment, and these alterations are likely mediated by maternal stress system. The maladaptive reproduction suppression seen in HL group suggests intrinsic population density as one of ecological factors generating delayed density-dependent effects.