Changes of Estrogen in Serum and Estrogen Receptor β in the Relevant Brain Regions Following Mating Behavior of the Male Mandarin Vole Microtus mandarinus

In order to investigate the estrogen and estrogen receptor β changes after mating behavior of male mandarin vole （Microtus mandarinus）, the radioimmunoassay （RIA） and immunohistochemistry methods were used to investigate changes of the serum estrogen （E） concentrations, estrogen immunoreactive neurons （E-IRs） and estrogen receptor β immunoreactive neurons （ERβ-IRs） in the relevant brain regions following mating behavior. Fifteen sexually matured male voles were randomly divided into three groups and treated differently： （1） control group： voles were exposed to clean hard-wood shavings （n=5）, （2） exposure group： voles were exposed to the soiled bedding for more than 24h on which estrous females had been placed （n=5）, and （3） mating group： voles were placed with an estrous female for more than 24h （n=5）. The results showed circulating serum E concentrations were significantly higher in the mating group than in the exposure group and the control group, and there were no significant difference between the exposure group and the control group. E-IRs and ERβ-IRs were detected in the following brain regions related to mating behavior： the arcuate nucleus （ARC）, bed nucleus of the stria terminalis （BST）, lateral septal nucleus （LS）, medial amygdaloid nucleus （ME）, medial preoptic area （MPO） and ventromedial hypothalamic nucleus （VMH）. The results showed that there were significantly more E-IRs in the six brain regions in the mating group than in the control group and the exposure group, and there were no significant difference between the exposure group and the control group except for LS. There was no significant difference in ERβ-IRs in the six brain regions among the three groups, and there were some lighter -stained ERβ-IRs in these brain regions. The results suggested that estrogen affect mating activity of male mandarin voles, but ERβ might not play an important role in mating behavior of male mandarin voles. Instead, it might be through other receptors.

捕食风险应激对雄性布氏田鼠及子代繁殖性能的影响

本研究旨在探讨雄性布氏田鼠暴露于捕食风险应激对自身及后代繁殖性能的影响,以及这种效应的阶段性。青春期是动物生长发育和对外界环境敏感的重要阶段,推测青春期所经历的捕食风险应激对雄鼠和后代繁殖性能的影响更为显著。实验选取90日龄成年期和28日龄青春期雄性布氏田鼠作为亲代,每天分别暴露于蒸馏水、兔尿和猫尿1 h,连续18 d。随后每组随机选取一半田鼠取样检测性腺器官指数、精子质量和数量等参数,另一半与正常雌鼠交配,待后代成年后检测繁殖性能。结果显示,与对照相比,成年期和青春期暴露于猫气味的雄性布氏田鼠精子正常率显著下降,精子畸形率和死亡率显著升高,而暴露于兔气味的雄鼠仅降低了正常精子比例;成年期雄性田鼠暴露于猫气味没有影响繁殖输出,而青春期暴露的雄鼠的后代在出生时雌性比例显著增加;成年期暴露于猫气味和兔气味都没有影响后代的繁殖性能,青春期暴露于猫气味的雄鼠的后代成年后性腺指数、精子密度和精子正常率降低,精子畸形率和死亡率显著升高,而暴露于兔气味仅降低了雄性后代的精子密度和精子正常率。以上结果验证了本研究假设,即捕食风险应激对布氏田鼠亲代和后代的繁殖性能均有一定的抑制作用,且青春期应激的效应更强更持久,存在明显的效应阶段依赖性。

Effects of fitch odor (Mustila eversmanni) on behavior and breeding of root voles (Microtus oeconomus)

From April to December in 1997 at Northwest Plateau Institute of Biology, Chinese Academy of Science, the effect of predation risk on social behavior, feeding, reproduction and sexual hormones of the root voles (Microtus oeconomus) was studied when the root voles (Microtus oeconomus ) were exposed to the odor of fitch (Mustila eversmanni). The results showed that the root voles delayed breeding period and the frequency of the copulation significantly lowered (P【0.01). Comparing with the control group, the accumulated time of amicable behavior in females, and general activity of both sexes increased significantly (P【0.01). The frequencies of general activity (P【0.01), investigating activity (females: P【0.05, males: P【0.01), and self-grooming (P【0.01) of both sexes were less significantly. At the same time, the amount of energy intake (P【0.05) and body weight (P【0.01) of the root voles decreased significantly. The litter weight and ovary index of females decreased (P【0.01). For males the sperm count in epididymides also decreased significantly (P【0.01). The progesterone in the blood serum of root voles females increased significantly under fitch odor (P【0.01).

Effect of temperature on antioxidant defense and innate immunity in Brandt’s voles

Ambient temperature is an importa nt factor in flue ncing many physiological processes, in eluding antioxidant defense and immunity. In the present study, we tested the hypothesis that antioxidant defense and immunity are suppressed by high and low temperature treatme nt in Bran dt's voles (Lasiopodomys brandtii). Thirty male voles were randomly assigned into different temperature groups (4, 23, and 32℃, n=10 for each group), with the treatment course lasting for 27 d. Results showed that low temperature in creased gross en ergy in take (GEI) and liver, heart, and kidney mass, but decreased body fat mass and dry carcass mass. With the decline in temperature, hydrogen peroxide (H2O2) concentration, which is indicative of reactive oxyge n species (ROS) levels, in creased in the liver, decreased in the heart, and was unchanged in the kidney, testis, and small intestine. Lipid peroxidation indicated by malonaldehyde (MDA) content in the liver, heart, kidney, testis, and small intestine did not differ among groups, implying that high and low temperature did not cause oxidative damage. Similarly, superoxide dismutase (SOD) and catalase (CAT) activities and total antioxidant capacity (TAOC) in the five tissues did not respond to low or high temperature, except for elevation of CAT activity in the testis upon cold exposure. Bacteria killing capacity, which is indicative of innate immunity, was nearly suppressed in the 4℃ group in contrast to the 23℃ group, whereas spleen mass and white blood cells were un affected by temperature treatment. The levels of testosterone, but not corticostero ne, were in flue need by temperature treatment, though neither were correlated with innate immunity, H2O2 and MDA levels, or SOD, CAT, and TAOC activity in any detected tissues. Overall, these results showed that temperature had different in flue nces on oxidative stress, an tioxida nt en zymes, and immunity, which depended on the tissues and parameters tested. Up-regulation or maintenance of an tioxida nt defe nse might be an importa nt mechanism for voles to survive highly variable environmental temperatures.

Mating behavior induces changes of expression of Fos protein,plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB) of the male mandarin vole Microtus mandarinus

In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus,the radioimmunoassay(RIA)and immunohistochemistry methods were used to investigate the differences in plasma testosterone(T)concentrations and distribution of T immunoreactive neurons(T-IRs),androgen receptor immunoreactive neurons(AR-IRs)and Fos protein immunoreactive neurons(Fos-IRs)in the accessory olfactory bulb(AOB)and the main olfactory bulb(MOB)following exposure to clean hard-wood shavings(control group),soiled bedding(exposure group)or contact with an estrous female(mating group).Results showed that plasma T concentration was significantly higher in the mating group than that in the exposure group,and both the mating group and the exposure group displayed significantly higher plasma T concentration than the control group.T-IRs,AR-IRs and Fos-IRs were investigated with the immunohistochemistry method in granule cell(GC)and mitral cell(MC)of the MOB and the AOB in the three groups.There were significantly more T-IRs,AR-IRs and Fos-IRs in MC and GC of the AOB in the mating group than that in the exposure group or the control group.T-IRs,AR-IRs and Fos-IRs did not show significant differences between the exposure group and the control group.Furthermore,obvious differences in MC and GC of the MOB were not found among the three groups.The results confirm that both changes of T and AR in the AOB might be underlying mating behavior in the adult male mandarin voles.

Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles(Microtus ochrogaster)

Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles （Microtus ochrogaster）. We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography （microCT） analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.

Interactions between intruders and residents in the mole vole Ellobius talpinus

We studied the behavioral and endocrine responses of the fossorial s ocial rodent, mole vole Ellobius talpinus Pall., to intrusions of strangers int o burrow systems that were occupied by intact families. Both in reproductive and non-reproductive seasons, all intruders disappeared from the burrow systems of residents within two days of introduction, whereas 4 of 7 individuals introduced into empty burrows remained there at least for two days. Introduction of strang ers led to the concentration of residents at the point of release and to an incr ease of plasma corticosterone in both residents and intruders. During the breedi ng season, introduction of strangers was also accompanied by an increase of plas ma testosterone of residents on the day of introduction. Thus, simulation of int rusion of strangers demonstrated the efficient social fence of resident mole vol es that seems to be an important mechanism of stabilization of size and structur e of mole vole families. Encounters of residents and intruders resulted in activ ation of physiological mechanisms of stress, especially during the breeding seas on .

青藏高原田鼠源多刺带绦虫囊尾蚴的鉴定及遗传进化分析

为鉴定我国青藏高原分离的田鼠源绦虫囊尾蚴的种类及其遗传进化特征,本研究通过对该囊尾蚴进行形态学观察,采用绦虫cox1基因通用引物,利用PCR扩增并测序,初步鉴定该囊尾蚴。形态学观察结果显示,该囊尾蚴为小型虫体,虫体背部和腹部稍扁平,长度约为200.0 mm,虫体横截面直径约为2.5 mm;虫体分为3部分:前端部分直径通常略小,中间部分表面为皱褶区域,约占整个虫体的一半,后端部分细长,相对光滑,有平行的横向凹陷;PCR结果显示,在约440 bp处出现与预期目的片段大小相符的条带,测序结果显示,该基因序列与多刺带绦虫(T.polyacantha)cox1基因序列(EU544581)的同源性高达97.0%。初步表明该囊尾蚴属于多刺带绦虫囊尾蚴。采用多刺带绦虫线粒体cox1、nad1和12S rRNA特异性基因引物经PCR进一步鉴定并测序。将3个基因测序结果与GenBank登录的多刺带绦虫的相应基因序列比对,分析它们之间的同源性,并构建这3个基因的进化树,分析它们之间的遗传进化关系。PCR结果显示,分别扩增到约390 bp(cox1)、480 bp(nad1)和240 bp(12S rRNA)的目的条带。同源性分析结果显示,3个基因序列与GenBank登录的多刺带绦虫相应基因序列的同源性最高分别达99.4%、98.7%和100.0%。进化树结果显示,该虫株的3个基因均与不同宿主的多刺带绦虫处于同一分支。本研究在国内首次鉴定到青藏高原田鼠源多刺带绦虫囊尾蚴,并分析其线粒体基因的同源性及遗传演化关系,为多刺带绦虫的分类、鉴定和种群遗传进化分析及分子流行病学调查等奠定了研究基础。

布氏田鼠焦虑样行为、反捕食行为及HPA轴水平的性别差异

为探讨布氏田鼠(Lasiopodomys brandtii)焦虑样行为、反捕食行为和下丘脑-垂体-肾上腺(hypothalamic-pituitary-adrenal, HPA)轴水平的性别差异,观测雌雄布氏田鼠在旷场、明暗箱和反捕食箱中的行为差异,及其HPA轴参与调控的促肾上腺激素(adrenalotropic hormone, ACTH)和皮质酮(corticosterone, CORT)水平的差异。结果表明:雄性布氏田鼠在旷场中移动的总距离和平均速度均显著高于雌性,而静止时间显著低于雌性布氏田鼠。雄性布氏田鼠进入明箱的次数与雌性布氏田鼠无显著差异,但在明箱中停留时间显著高于雌性布氏田鼠。暴露于捕食者猫气味时,雌性布氏田鼠仅移动行为的持续时间显著高于雄性布氏田鼠。雌性布氏田鼠血浆中ACTH和CORT浓度显著高于雄性布氏田鼠。综上,布氏田鼠的活动性、焦虑样行为、反捕食行为及HPA轴水平均存在性别差异,提示野生布氏田鼠受其自身内分泌水平的影响,雌雄个体采取截然不同的行为策略以适应当前环境,从而有利于其种群的稳定。

布氏田鼠盲肠中纤维素分解菌的分离鉴定及其产酶条件优化

纤维素在纤维素分解菌的作用下分解成可利用的物质,有利于改善环境污染和缓解能源危机。布氏田鼠是主要分布在我国内蒙古草原上的一种植食性动物,其盲肠微生物种类丰富。从布氏田鼠盲肠中筛选具有高效分解纤维素能力的菌株,并对筛选的菌株进行鉴定及纤维素酶的酶学特性分析。结果表明:刚果红染色法初筛出8株具有分解纤维素能力的菌株,发酵法复筛出分解能力最强的菌株T1,形态学观察及分子生物学鉴定确定该菌株为枯草芽孢杆菌(Bacillus subtilis strain)。菌株T1以1.5%玉米粉作为碳源、1%蛋白胨作为氮源、接种量5%时产纤维素酶量最高。该纤维素酶最适反应pH值4.8,最适反应温度40℃,最佳反应时间40 min,且具有一定的酸碱耐受性和热稳定性,这一研究为纤维素的开发利用提供理论依据。

温度驯化对布氏田鼠肝脏温敏瞬时受体电位通道蛋白表达的影响

肝脏是哺乳动物基础代谢产热的关键器官。温敏瞬时受体电位通道蛋白(Thermosensitive transient receptor potential channels,Thermo-TRPs)参与了调控肝细胞的生理功能。为了解Thermo-TRPs是否参与肝脏的代谢产热,以成年布氏田鼠(Lasiopodomys brandtii)为研究对象,测定了不同驯化温度下6种Thermo-TRPs在肝脏中的表达,分析其与肝脏产热相关蛋白和信号通路蛋白的关系。结果显示:(1)与高温组相比,低温增加了肝脏解偶联蛋白1(uncoupling protein 1,UCP1)的表达;而与常温组相比,低温降低了肝脏解偶联蛋白3(uncoupling protein 3,UCP3)的表达;(2)6种Thermo-TRPs均在肝脏中表达,与高温组相比,低温显著降低了TRP vanilloid 4(TRPV4)的表达,同时显著增加了腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)的表达;(3)低温显著增加了布氏田鼠血清三碘甲状腺原氨酸(T_(3))水平,提高了T_(3)/T_(4)比值;T_(3)/T_(4)比值与肝脏UCP1和AMPK呈显著正相关,肝脏中UCP1与TRPM2和AMPK呈显著正相关。这些结果表明,肝脏TRPV4和AMPK可能参与了低温环境中代谢产热等生理功能的调节过程。

哺乳期高温经历导致布氏田鼠F1代的热中性区变窄

哺乳期是影响小型哺乳动物发育的关键时期,但关于哺乳叠加高温对后代代谢可塑性的影响,尚不清楚。为研究哺乳期母体(F0)高温经历对后代(F1代和F2代)能量代谢特征的影响,我们测定了哺乳期母体经历高温(30±1)oC的布氏田鼠(Lasiopodomys brandtii)F1代和F2代成体以及常温(23±1)oC经历的后代成体(作为对照)的体重和体温,采用开放式呼吸代谢仪测定不同环境温度暴露3 h后的代谢率,并计算热传导和呼吸商。哺乳期高温经历的F1代动物在成年期的体重显著低于常温对照组和高温经历的F2代动物。在5~33.5 oC环境温度范围内,布氏田鼠维持稳定的体温;35 oC高温胁迫时,常温组、高温经历F1代和F2代的体温均显著下降。常温组布氏田鼠的热中性区为27.5~33.5 oC,高温经历F1代的热中性区下临界温度点30 oC,热中性区比常温组变窄(30~33.5 oC),高温经历F2代的热中性区与常温组相比无变化。在热中性区温度以上,热传导随环境温度的升高而显著增加,高温经历的F1代和F2代布氏田鼠热传导增加的起始温度点升高。呼吸商随环境温度的升高明显增加,但不受哺乳期高温经历的影响。结果表明,哺乳期母体高温经历导致布氏田鼠F1代成年后的体重降低,热中性区变窄,提高了F1代动物在高温环境下的代谢可塑性,但这种影响并未持续到F2代。这些研究结果揭示了哺乳期母体高温(热浪)对小型哺乳动物后代体型和热中性区的长期影响,以及由此引起的对种群动态的潜在效应。

Small mammal community composition impacts bank vole (Clethrionomys glareolus) population dynamics and associated seroprevalence of Puumala orthohantavirus

Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans.Biodiversity is hypoth-esized to be closely related to pathogen prevalence through multiple direct and indirect pathways.For example,the presence of non-host species can reduce contact rates of the main reservoir host and thus reduce the risk of transmission(“dilution effect”).In addition,an overlap in ecological niches between two species could lead to increased interspecific competition,potentially limiting host densities and reducing density-dependent pathogen transmission processes.In this study,we investigated the relative impact of population-level regulation of direct and indirect drivers of the prevalence of Puumala orthohantavirus(PUUV)in bank voles(Clethrionomys glareolus)during years with high abundance.We compiled data on small mammal community composition from four regions in Germany between 2010 and 2013.Structural equation modeling revealed a strong seasonality in PUUV control mechanisms in bank voles.The abundance of shrews tended to have a negative relationship with host abundance,and host abundance positively influenced PUUV seroprevalence,while at the same time increasing the abundance of competing non-hosts like the wood mouse(Apodemus sylvaticus)and the yellow-neckedfield mouse(Apodemusflavicollis)were associated with reduced PUUV seroprevalence in the host.These results indicate that for PUUV in bank voles,dilution is associated with increased interspecific competition.Anthropogenic pressures leading to the decline of Apodemus spp.in a specific habitat could lead to the amplification of mechanisms promoting PUUV transmission within the host populations.

基于无人机遥感和深度学习的布氏田鼠洞群识别

草原鼠害是典型的次生灾害,是草原退化引起的一种生物灾害,发生后不仅加剧草原退化程度,也会引起鼠疫等极度危险的传染病。因此,精确、及时监测鼠害状态对防治鼠害、草原退化工作具有重要实际意义。以内蒙古呼伦贝尔和锡林郭勒草原区发生的布氏田鼠灾害区为例,通过野外实地调查,采集了5个不同生境区无人机正射影像,分析每个区域布氏田鼠洞群结构和影像特征,并采集和建立样本库,分别构建深度学习(SSD、RetinaNet、YOLOv3和Faster R-CNN)识别模型,进行了布氏田鼠洞群识别。结果表明:Faster R-CNN模型在准确率上表现出更高的可靠性,其mAP达到了84.4%;SSD模型效果最弱,mAP只有45.4%,但在检测速度上较快。因此,可采用Faster R-CNN模型作为布氏田鼠洞群识别模型的核心算法。

熟悉性对棕色田鼠和根田鼠择偶行为的影响

以两性配对共居至交配或生仔作不同熟悉处理 ,在Y字型选择箱中分别观察棕色田鼠、根田鼠的择偶行为和配偶识别。结果如下 :(1)棕色田鼠雌雄两性均表现出对熟悉异性或配偶的喜好倾向 ;(2 )在根田鼠中 ,只有雌性表现出对熟悉雄鼠或配偶的选择倾向 ,雄鼠无明确的选择取向 ;(3)每种雌性田鼠对 2种熟悉性不同的同种雄性的嗅舔时间均有显著差异性 ,而每种雄性田鼠对 2种熟悉性不同的同种雌性的嗅舔时间均无显著差异性。这些结果表明 :(1)熟悉性对棕色田鼠择偶行为的影响大于对根田鼠的影响 ;(2 )嗅舔时间差异可反映不同田鼠的配偶识别能力 ,熟悉性对棕色田鼠配偶识别能力的影响大于对根田鼠的影响 ;(3) 2种田鼠配偶识别的性别差异的一致性 ,提示这 2种田鼠的雌性配偶识别能力均强于雄性田鼠 ,而雌鼠的配偶识别能力可能取决于雌鼠受交配或分娩刺激的生理状态 ;(4 )棕色田鼠室内所表现的择偶行为的两性熟悉性特征与其单配制有关 ,根田鼠所表现的择偶行为的雌性熟悉性特征与其一雄多雌制有关。

棕色田鼠与沼泽田鼠犁鼻器和副嗅球的组织结构

用组织学方法研究了棕色田鼠 (Microtusmandarinus)、沼泽田鼠 (M .fostis)副嗅球和犁鼻器的结构及其在两种鼠间的差异 ,以此探讨两种田鼠的进化机制与适应功能。两种田鼠的犁鼻器位于鼻腔前端鼻中隔基部的两侧 ,呈管状结构 ;沿着犁鼻器的长轴犁鼻管呈现不同的形态学特征 ,犁鼻管直接开口于鼻腔 ,从前向后沿着长轴旋转 ,中间管壁 (犁鼻粘膜 )变成底部 ,侧面管壁 (假覆层上皮 )变成犁鼻管顶壁 ,最终犁鼻管变小成为一个腺体的分支 ,不同部位具有不同的组织学特征。通过选取中间相似部位对两种田鼠进行比较研究 ,发现棕色田鼠犁鼻粘膜比沼泽田鼠厚 ,而其长度却短于沼泽田鼠。棕色田鼠副嗅球颗粒细胞带宽和僧帽细胞带宽均大于沼泽田鼠 ,而带长却小于沼泽田鼠。相关分析发现 ,犁鼻器和副嗅球形态有一定的对应关系 ,这可能和两个结构之间存在着神经投射有关。棕色田鼠幼体的犁鼻粘膜、神经细胞核、假覆层上皮。

洞庭湖区东方田鼠繁殖特性研究

１９９２年１月～１９９４年１２月，作者在东洞庭湖区岳阳县麻塘区调查，３年捕获并剖检东方田鼠１３９２只，其中雌鼠５９９只，雌性比♀／（♂＋♀）＝４３．０％。该鼠全年繁殖，盛夏５～７月怀孕率较低，冬季１２～２月怀孕率比同域其它鼠种显著偏高。３年合计总怀孕率为２９．２％．平均胎仔数（ｘ±ＳＥ）为５．１３±０．１２只，平均窝仔数４．６０±０．２７只，雌鼠和雄鼠的繁殖强度随年龄增长而递增。室内饲养的东方田鼠妊娠期约２０天，窝仔数４．３３±０．３３只，雌鼠５０～６０天成熟，雄鼠稍迟。枯水期（１１月～翌年４月）东方田鼠主要栖息于湖洲草地，汛期（５～１０月）主要栖息于过垸内稻田。在不同栖息地其繁殖力差别较大，湖洲的繁殖强度最高，稻田区次之，岗地最低，反映它在各栖息地生态适合度不同。文中还对全国４个亚种的繁殖参数作了比较。

布氏田鼠标志种群的繁殖参数

采用标志重捕和染色观测法跟踪了内蒙古典型草原区布氏田鼠野外种群 ,按绝对时间年龄研究其种群繁殖参数。结果表明 :4～ 5月份出生的雄鼠能在当年达到性成熟 ,性成熟发育历期约为 1 5个月 ,6月后出生的雄鼠当年达不到性成熟。在达到性成熟的当年雄鼠中 ,多数个体再度转入性休止期 ,其平均繁殖结束时间要比越冬雄鼠早 1个月 ,而越冬雄鼠则在整个繁殖期保持性活动状态。雌鼠性成熟发育历期约为 1个月 ,首次产仔时间约为2月龄。雌鼠在一年中的产仔窝数与其年龄有关 :越冬鼠能产 3～ 4窝 ,4月份出生的雌鼠能产 2～ 3窝 ,5月份出生的雌鼠当年能产 1～ 2窝 ,6月份出生的雌鼠能产 0～ 1窝 ,7月份之后出生雌鼠当年不参加繁殖。在自然条件下 ,布氏田鼠一生中最多能产

灭鼠后布氏田鼠种群特征的研究

1987和1988年4—5月,笔者在内蒙古正镶白旗布氏田鼠危害严重的草场上,连续两年用药物灭鼠。调查结果表明,在布氏田鼠种群数量上升或下降的年份,春季灭鼠均能控制当年的鼠害。鼠密度高时,灭鼠后鼠种群年龄结构、性比、怀孕率和睾丸下降率均发生改变。鼠密度低时,灭鼠对种群特征影响不显著。

大绒鼠体温调节和产热特征

大绒鼠为横断山脉地区小型哺乳动物的典型代表 ;其体温仅能在 1 5～ 30℃范围内维持稳定 ;在热中性区内 ,最低静止代谢率为 2 71± 0 1 3mlO2 /g h,为其体重预期值的 2 0 3 2±1 0 1 3 % ;F -值 { (RMR/Me) /(Cm/C’) }为 0 99± 0 0 5 ;在 2 5℃的NSTmax为 5 1 8± 0 1 9mlO2 /g h ;BAT重量为 0 33± 0 0 5g,为体重的 0 84% ,BAT细胞线粒体的产热活性较高 ;肝脏也具有较强的产热活性。大绒鼠的产热特征和体温调节模式很可能反映了横断山地区小型啮齿动物的特征。