银狐气味对根田鼠繁殖和觅食的影响

在实验室条件下, 主要测定银狐的气味对根田鼠社会行为、觅食、繁殖特征及性激素水平的影响, 并探讨银狐气味使根田鼠产生繁殖迟滞的机制。结果表明, 银狐气味对82 %的配对根田鼠产生显著的繁殖迟滞, 对根田鼠一般动作、探究、自我修饰及婚配行为的频次具有显著的抑制作用( P < 0105) 。对各种行为累积时间的作用则产生明显的性别差异, 银狐气味可提高雄体及雌体一般动作及雌体亲密行为的累积时间; 对雄体自我修饰行为, 以及雌体攻击、探究及自我修饰行为的累积时间有显著的降低作用( P < 0105) 。雄体附睾精子计数、雌体卵巢指数及胚胎重量极显著地减低( P < 0101) , 相应地, 雌体血清孕酮显著地提高( P< 0101) 。     

艾鼬气味对根田鼠社会行为和繁殖的影响

在实验室条件下 ,主要测定艾鼬 (Mustelaeversmanni)气味对根田鼠 (Microtusoeconomus)社会行为、繁殖特征及性激素水平作用的格局 ,并探讨艾鼬气味使根田鼠产生繁殖迟滞的机制。结果表明 ,艾鼬气味对根田鼠一般动作、探究、自我修饰及婚配行为的频次具有显著的抑制作用 (P <0 0 5 ) ,而对各种行为累积时间的作用则产生明显的性别差异。艾鼬气味可提高雄体及雌体一般动作及雌体亲密行为的累积时间 ;对雄体自我修饰行为 ,以及雌体攻击、探究及自我修饰行为的累积时间有显著的降低作用 (P <0 0 5 )。艾鼬气味能显著制约根田鼠对食物的摄入 (P <0 0 5 ) ,并使其体重显著 (P <0 0 1)降低。在艾鼬气味条件下 ,82 %的配对根田鼠产生显著的繁殖迟滞 ,其雄体附睾精子计数、雌体卵巢指数及胚胎重量极显著地减低 (P <0 0 1) ,相应地 ,雌体血清孕酮显著地提高 (P <0 0 1)。上述结果验证了本文提出的捕食风险使田鼠类动物产生繁殖迟滞的假设     

根田鼠气味识别的性二型

以新鲜尿和粪作气味源,在行为选择箱中观察根田鼠的行为识别模式,结果表明：雌鼠对陌生同性尿、粪气味源行为识别的差异不显,雄鼠对陌生同性尿、粪气味源的行为识别在多个指标上存在显差异;根田鼠对陌生异性尿、粪的行为响应模式无明显差异;除嗅舔时间外,雌、雄鼠对粪气味的行为识别在其他指标上不存在明显差异;比较雌、雄鼠对尿刺激的行为识别发现,雄鼠对尿刺激的访问频次和反标记显大于雌鼠,雌性嗅舔时间显大于雄性,其他方面二之间并无显差异。因此,雌、雄性根田鼠对粪气味的行为识别模式不存在性别差异;对尿气味的行为识别模式存在性别差异。     

基于交叉抚育的雄性根田鼠对异性同胞尿气味的识别

通过交叉抚育建立室内繁殖种群,在断奶后（80日龄）分别取这些供体的新鲜尿气味作刺激物,在行为观察箱中观察和记录雄性根田鼠对雌鼠气味的行为反应,以研究根田鼠同胞识别的化学通讯机制。结果表明：①在不同的发育时期（2～70日龄）,雄性同巢同胞与异巢同胞的体重没有显著差异。②雄性根田鼠对雌性同巢非同胞气味的接近潜伏期显著长于对异巢非同胞的接近潜伏期（P〈0．05）,其对异巢非同胞气味的访问时间和嗅舔时间都显著高于同巢非同胞气味（P〈0．05）。③雄性根田鼠对雌性异巢同胞和异巢非同胞气味的不存在明显偏好。其对两者的接近潜伏期、访问频次、访问时间、嗅舔频次和嗅舔时间等行为响应均无显著差异（P〈0．05）。这些结果表明,80日龄时,雄性根田鼠能够识别熟悉和陌生的无亲属关系雌性尿气味,但不能区分陌生的亲属和非亲属,因此,其异性同胞识别的机制为共生熟悉模式。     

根田鼠对不同亲属关系异性尿气味的识别

根为检验根田鼠对不同亲属关系异性成体尿气味的识别能力,通过一雄两雌配对实验建立实验种群,从而产生同胞、父系半同胞和陌生个体。在行为选择箱中记录了雌、雄根田鼠对亲属系数分别为0、0.25 和0.5 异性尿气味的行为响应模式。结果如下:雌性根田鼠对3 种不同亲属关系雄鼠气味的接近潜伏期的差异达到极显著水平(P < 0.01),嗅闻时间的差异也达到显著水平(P <0.05),而嗅闻频次和反标记的差异均未达到显著水平(P >0.05)。雄性根田鼠对3 种不同亲属关系雌鼠气味的接近潜伏期和嗅闻时间的差异都未达到显著水平(P >0.05)。对不同亲属关系的气味嗅闻频次和反标记的比较分析表明,三者间的差异也未达到显著水平(P >0.05)。因此,雌性根田鼠能够识别不同亲属关系异性气味并对不同气味表现出不同的行为响应模式;而雄鼠不能识别3 种气味并对其表现出类似的行为模式。     

雌性根田鼠的亲属识别与配偶选择

在Y字型选择箱中进行3种不同熟悉处理的配偶选择实验以检验动情雌性根田鼠配偶选择时的亲属识别和近交回避。（1）动情雌鼠在熟悉雄性同胞和陌生非同胞之间嗅添频次和时间、及自我修饰时间的差异非常显著（P＜0.01),所作的脊柱前凸反应时间也有显著差异（P＜0.05),这些行为均多针对于陌生非同胞雄性。结果提示动情雌性根田鼠在熟知雄性同胞身份的条件下对陌生非亲属雄性的气味更感兴趣,在择偶中与非亲属雄性交配来实现近交回避。（2）动情雌鼠对陌生雄性非同胞的嗅添频次和时间及所作的脊柱前凸反应时间显著大于陌生同胞雄性（P＜0.05),而针对陌生雄性非同胞自我修饰时间非常显著地大于针对陌生雄性同胞（P＜0.01)。这说明动情雌性根田鼠在择偶时可以识别断奶后分离不熟悉的雄性亲属,而在交配行为上偏向于非亲属雄性。（3）动情雌鼠在熟悉雄性同胞和非同胞之间跃添时间差异明显（P＜0.05),嗅添频次的差异更甚（P＜0.01);所作的脊柱前凸反应时间和社交后自我修饰时间差异也非常显著（P＜0.01),这些行为也均都偏向于非同胞雄性;结果提示断奶后继续熟悉可维持动情雌鼠对雄性亲属的嗅觉识别记忆力,在交配行为上主动回避亲属雄性。故认为：断奶后嗅觉识别持久力是发情雌性根田鼠亲属识别的机制,亲属识别是最初发情的雌性根田鼠配偶选择中近交回避的首要途径和机制,熟悉性是维持雌性根田鼠配偶选择实现近交回避的机制和特征。     

果子狸繁殖期行为的观察

描述了果子狸在繁殖期表现出的１７种子体为、１４种神群行为和交配模式。个体行为包括侧卧、叭、蹲、静立、双脚站立、食粪、理毛、抓痒、嗅闻、标记,发情叫、雄性鸣咽声、舔阴茎、咬阴部、食交配栓;社会行为包括仪式化格斗、雌性雄必与的抵抗、打斗、依偎、同性或异性之间彼此舔毛、雄性嗅闻雌性阴部及尿液、舔雌性阴部和错爬胯,交配行为主要在夜间进行,其交配模式为无锁结（可能）多次插入、插入后抽动、一次、性射精并在射精     

外源性皮质酮对雄性根田鼠交配行为的作用

本文研究了皮质酮对雄性根田鼠交配行为的作用。实验个体分别注射0.10 ug/ g体重、0. 60 ug / g体重和1.00 ug/ g体重剂量的皮质酮,1 h后测定每只雄性根田鼠的交配行为。结果显示,3 个处理组动物具有射精能力的个体比率及其爬跨、抽动和射精潜伏期与对照组动物相比均无显著差异,爬跨和抽动频次也无显著变化。不同处理组个体的血浆睾酮含量无显著差异。因此,皮质酮没有影响雄性根田鼠的交配行为和性激素的分泌。该结果提示,哺乳动物在急性应激条件下所分泌的皮质酮可能不参与对性行为的调控。     

雌性根田鼠断奶后对亲本尿气味的记忆

为研究亲子分开后雌性根田鼠对亲本气味的记忆持续时间，分别在未分开（20日龄）、分开10 d（30日龄）、20 d（40日龄）、30 d（50日龄）、40 d（60日龄）时，以新鲜尿作气味源，在行为观察箱中记录雌性根田鼠对不同气味源的行为响应模式，结果表明：(1) 未分开时，雌鼠遭遇父本气味时自我修饰的频次极显著高于陌生雄鼠气味，在分开10 d时，雌鼠接近父本气味的频次显著多于接近陌生雄鼠气味的频次，其对前者反标记显著少于后者；(2)分开20 d后，雌鼠对父本和陌生雄鼠气味的行为响应无明显差异；(3) 未分窝时，雌性根田鼠幼仔对母本和陌生雌鼠气味的行为响应无差异；（4）分开10—40 d时，雌性根田鼠对母本和陌生雌鼠气味表现出不同的行为响应模式。以上结果表明，在亲子分开10 d时，雌鼠仍能识别父本和陌生雄鼠的气味；分开20 d后，雌鼠不再能够识别父本和陌生雄鼠的气味；在亲子分开40 d时，雌鼠仍能识别母本和陌生雌鼠的气味。因此，雌鼠对父本气味的嗅觉记忆时间可以持续到亲子分开10—20 d之间；而对母本气味的嗅觉记忆时间则可以持续到亲子分开40 d以上。     

根田鼠瞬时摄入率对植物可利用性变量集功能反应的格局

在实验室条件下,以随机区组设计的新鲜紫花苜蓿叶片斑块,测定苜蓿叶片可利用性变量,叶片密度,生物量密度和叶片大小对根田鼠瞬时摄入率的作用格局。苜蓿叶片大小对根田鼠摄入率具有显作用（P＜0．01）,而叶片密度与生物量作用则不显（P＞0．05）;根田鼠摄入率对其口量变化能作出2倍以上的反应（P＜0．01）;观测摄入率与模型预测摄入率的回归显（P＜0．01）,研究结果证明,以叶片大小替代根田鼠口量是影响其摄率的独立变量;检验了植物大小是替代植食性哺乳动物口量的有效变量,以及植物大小是影响植食性哺乳动物摄入率潜在独立变量的假设。     

小型啮齿动物种群系统调节复合因子理论的野外实验研究：食物可利用性和捕食对根田鼠种群空间行为的作用模式及其对种群调节的探讨

本项研究在野外围栏条件下,采用析因实验设计,测定食物可利用性和捕食对根田鼠（Ｍｉｃｒｏｔｕｓｏｅｃｏｎｏｍｕｓ）种群空间行为的作用模式。检验的特定假设为,高质量食物较大的可利用性能降低田鼠的攻击行为和活动;捕食能减少田鼠的活动。研究结果表明,食物可利用性能间接地和直接地影响根田鼠的空间行为。附加食物种群具有较高的密度和较小的巢区,且在诱捕期间具有较少的长距离活动和较低的攻击水平。捕食者的存在不直接影响攻击行为,但能影响诱捕期间的长距离活动,此为根田鼠对捕食者存在作出的直接反应。在阐明田鼠种群动态时,应仔细考虑上述因子相互作用的效应。     

Root vole movement patterns: do ditches function as habitat corridors?

1. Ditches are often connected to root vole habitat patches (i.e. moist reed patches) in the Netherlands. Due to the linear structure of ditches and because ditch habitat is qualitatively similar to root vole habitat patches, we hypothesized that ditches could function as habitat corridors facilitating dispersal movement of root voles. In order to test this hypothesis, we radiotracked root voles released in a landscape novel to them, consisting of ditches and agricultural meadows.
2. Agricultural meadows often surround the marsh patches inhabited by root voles. As the meadows are mowed regularly, we included the length of the meadow vegetation as an experimental factor in the study.
3. Assuming that ditches function as habitat corridors, we expected root voles in the ditches to move faster and more unidirectionally than root voles in the meadows, and to prefer the ditches to meadows.
4. We found that the ditches did not facilitate faster movements than the meadows. Although the root voles moved back and forth within the ditches, they showed a more directional movement pattern than the root voles in the meadows. Furthermore, the root voles preferred the ditch habitat irrespective of the vegetative cover in the meadow.
5. We conclude that ditches could function as habitat corridors for root voles, as they preferred to move in ditches when in unfamiliar areas.     

局部环境增温对根田鼠冬季种群的影响

通过建立开顶式增温小室模拟全球变暖的实验, 对海北高寒草甸地区实验增温样地及其对照样地内根田鼠的冬季种群进行调查, 旨在研究局部增温对根田鼠冬季种群的可能影响。结果表明, 在冬季, 实验增温草甸样地和灌丛样地内根田鼠的种群密度均显著高于其对照( P < 0.05) ; 实验增温灌丛样地与对照间性比的差异不显著( P > 0.05) ; 增温样地和对照之间、不同植被类型的增温样地之间、对照样地之间, 根田鼠留存率、平均体重及年龄结构的差异均不显著( P > 0.05) ; 有从对照样地向增温样地单方向迁移的记录。总之, 局部环境增温导致实验样地内根田鼠的冬季种群密度明显上升, 而其性比、存活率、种群平均体重以及年龄结构无明显变化; 在冬季, 根田鼠有从对照样地向增温样地扩散或迁移的趋势。     

Demographic responses to a mild winter in enclosed vole populations

Mild winter weather causing snow to melt and ice to accumulate on the ground has been proposed to cause the decreased survival of individuals, and less pronounced cyclicity, of small rodent populations in Fennoscandia. However, detailed data linking ice accumulation to decreased winter survival is lacking. We live-trapped and monitored with passive integrated transponders enclosed populations of root voles (Microtus oeconomus) exposed to different amounts of ice accumulation through a mild winter. We studied how social behaviour and survival responded to snow melt and ice accumulation. Voles avoided ground ice by moving their home ranges, thus increasing home range overlap in enclosed populations experiencing more extensive ice cover. Winter survival was not affected by the amount of ice accumulation, and was only slightly reduced during ice formation in early winter. The lowest survival rates were found at the onset of snow melt in early spring. These results suggest that ice accumulation does not cause lower survival during mild winters, probably because plastic social behaviour enables root voles to reduce the negative effects of varying winter weather on survival. The mechanisms for lower survival during mild winters may operate during spring and be related to spring floods or increased susceptibility to predators. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effects of food availability on proceptivity: A test of the reproduction at all costs and metabolic fuels hypotheses

Proceptive behaviours are used by animals to indicate interest in opposite-sex conspecifics. These behaviours can be affected by an individual's nutritional status. Two mutually exclusive hypotheses have been proposed to account for the effects of food availability on reproduction. These are the metabolic fuels hypothesis and the reproduction at all costs hypothesis. It is not known if food availability affects proceptive behaviours such as scent marking, over-marking, and self-grooming. In this study, we tested the hypothesis that food-deprived and nonfood-deprived meadow voles, Microtus pennsylvanicus, differ in the number of scent marks they deposit, the proportion of over-marks they deposit, and the amount of time they spend self-grooming when they encounter the scent marks of opposite-sex conspecifics. We tested this hypothesis by exposing meadow voles that either had continuous access to food or were food-deprived for either 6hours or 24hours to the scent marks of an opposite-sex conspecific. Due to differences in the natural history of male and female meadow voles, we predicted that female voles' behaviour will best be explained by the metabolic fuels hypothesis whereas males' behaviour will best be explained by the reproduction at all costs hypothesis. We found that both male and female voles deprived of food for either 6hours or 24hours spent less time self-grooming compared to nonfood-deprived voles. However, food availability did not affect the scent marking and over-marking behaviour of male and female voles. Differences in the effects of food availability on these proceptive behaviours are discussed within the context of the natural history of meadow voles.     

Identification of tannin–degrading microorganisms in the gut of plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus)

Gut microorganisms are thought to play a role in the degradation of plant secondary metabolites in herbivores. Here, we examined the presence of tannin–degrading microorganisms in the gut of two herbivores, plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus). Tannase activity in the feces of wild plateau pikas and root voles increased from June to August, corresponding to the increase in condensed and hydrolyzable tannin concentrations in plants during this period. Using intragastric tannic acid infusion, we found that tannase activities were significantly higher following administration of three concentrations of tannic acid than that in the control group for root voles. In contrast, for plateau pikas, animals administered tannic acid exhibited lower tannase activity in low–dose and high–dose groups than that in the control group. Tannase activities in root voles were higher than those in plateau pikas among different months and in different tannic acid infusion groups. Three tannin–degrading anaerobic strains were isolated from the cecum of plateau pikas (termed A1, A2, and A3) and root voles (termed M1, M2, and M3). 16 s rDNA sequencing assigned isolates A1 and M1 to the genus Enterobacter, A2 and M2 to the genus Shigella, and A3 and M3 to the genus Staphylococcus. These data provided the first evidence of microorganisms with tannin–degrading activity in the gut of plateau pikas and root voles. We speculated that both animals could degrade tannins in the gut, but that root voles would have a greater ability to process tannins than plateau pikas.     

球虫感染与捕食对根田鼠繁殖性能的影响

在自然界,捕食者和寄生物是两种主要的种群外部调节因子,二者的交互作用会对猎物和宿主种群波动产生深远影响。较低的球虫感染强度与捕食对根田鼠（Alexandromys oeconomus）繁殖无显著的交互作用。自然界球虫感染存在季节性变化,秋季感染强度最高。为了探究较高感染强度下,球虫与捕食对根田鼠繁殖的主效应及交互作用,本研究采用2×2析因实验设计,在野外围栏中测定了根田鼠种群肠道内寄生物的感染率和感染强度、雄性睾丸指数、睾酮水平、精子密度、精子活力以及雌性卵巢指数。结果表明,较高的感染强度下,球虫能显著抑制根田鼠的繁殖性能,但球虫感染与捕食对根田鼠的繁殖无显著的交互作用,这可能与球虫感染和捕食效应在时间上的错配有关。本研究认为,球虫感染对繁殖期小哺乳动物种群的调节作用虽有限,但其可通过与捕食者的耦合来降低宿主越冬时的存活率,进而影响宿主种群波动。     

Seasonal changes in the concentrations of plant secondary metabolites and their effects on food selection by Microtus oeconomus

Using cafeteria trials conducted during June–September 2008 in Qinghai Province, China, we investigated the selection of 20 plant species by root voles (Microtus oeconomus). It was found that both favored and edible plant groups of root voles comprised 6 species, while the remaining 8 species were anorectic plants. Three plant secondary metabolites (PSMs): flavonoids, condensed tannins, and total phenols, exhibited seasonal changes in concentration; being lowest at June and gradually increasing from July to August/September. Total phenols was the only factor included in the best model of generalized linear models, indicating that total phenols was the most important factor deterring food selection by root voles. In contrast, tannins had a weak effect on food selection by root voles. This study indicated that PSMs play an important role in food selection by root voles; however, the effects of PSMs depend on the type of PSMs. Furthermore, this finding partly verifies the hypothesis that PSMs contribute to the defense strategy of plants, significantly influencing plant selection by root voles.     

极田鼠基础代谢率对单宁酸反应的格局

采用Kalabukhov-skvortsov封闭式流体压力计测定根田鼠基础代谢率对食物单宁酸的反应格局。在食物蛋白质为10％条件下,摄入3％单宁酸食物的根田鼠在第5天、10天和20天的基础代谢率分别较第0天增高10．94％、20．82％及23．54％;摄入6％单宁酸食物的根田鼠在第5天、第10天和第20天的基础代谢分别较第0天增高18．67％、29．07％及27．71％、当食物蛋白质为20％时,摄入3％单宁酸食物的根田鼠在第5天、第10天和20天的基础代率分别较第0天增高6．67％、10．63％及11．21％;摄入6％单宁酸食物的根田鼠在第5天、第10天和20天的基础代谢率分别较第0天增高9．01％、14．50％及16．09％。说明,食物单宁酸能显地增加根田鼠的基础代谢率,充分检验了单宁酸使植食性小哺乳动物基础代谢率增高的假设。     

人工饲养条件下根田鼠肥满度的研究

实验室条件下,利用根田鼠1～70日龄体重和体长数据,计算其肥满度指数,目的在于分析其生长发育的基本规律。结果表明,根田鼠1～70日龄肥满度存在性别差异且随日龄增加而增大;雌雄个体的发育不同步;常见曲线回归模型对根田鼠1～70日龄的肥满度不能准确拟合,根据其生长发育状况,将其划分为3个阶段(其中幼体和成体阶段各含2个阶段)。