早期应激与当前环境对肠道寄生物感染根田鼠（Microtus oeconomus）的耦合效应

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	早期应激与当前环境对肠道寄生物感染根田鼠（Microtus oeconomus）的耦合效应
	聂绪恒
学位类型	硕士
导师	边疆晖
	2014-05
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	动物学
关键词	根田鼠寄生物球虫早期应激当前环境耦合作用
摘要	寄生物广泛存在于小哺乳动物中，且在小哺乳动物种群调控中具有重要的作用。但是，在野外围栏条件下，早期应激与当前环境对小哺乳动物肠道寄生物感染的影响未见报道。因此，在自然条件下开展寄生物与小哺乳动物种群关系的研究，对进一步认识和理解寄生物在小哺乳动物种群调控中的作用及其对有害动物的生物防控具有重要意义。本研究以根田鼠（Microtus oeconomus）为研究对象，在中国科学院海北高寒草甸生态系统定位站，采用围栏调控实验方法，于2012年4月分别建立高密度和低密度母体种群；于2012年8月中旬，用母体种群中出生的F1代个体建立4个子代种群：（1）来自亲本高密度的高密度子代种群（HH）；（2）来自亲本高密度的低密度子代种群（HL）；（3）来自亲本低密度的高密度子代种群（LH）；（4）来自亲本低密度的低密度子代种群（LL）。通过标志重捕和新鲜粪便的采集，测定其种群参数（种群密度和幼体补充率），粪便皮质酮含量以及寄生物的感染参数（感染率和感染强度），以分析处理对根田鼠感染其肠道寄生物的效应，为进一步研究寄生物在根田鼠种群波动中的作用奠定基础。本研究主要结果为：（1）感染根田鼠肠道的寄生物为球虫、绦虫和线虫。其中，球虫是主要寄生物，Eimeria wenrichi为球虫中的优势种，其感染随时间而显著变化；在幼体根田鼠中，高密度处理组对球虫E.wenrichi的感染显著高于低密度处理组；幼体根田鼠对E.ochrogasteri感染显著高于成体；本研究未发现球虫感染参数在根田鼠性别间的差异。（2）在不同处理子代种群中，早期应激与当前环境对根田鼠的球虫感染有显著的交互作用，HH组的E.wenrichi感染率显著高于LH和HL组，LL组的E.wenrichi感染率显著高于LH和HL组。而繁殖活动则可显著增加球虫对根田鼠的感染。（3）早期应激与当前环境对球虫感染根田鼠的效应不能传递到F2代。（4）在越冬后的子代繁殖种群中，HH组和HL组间的E.wenrichi的感染率和感染强度无显著差异，这与HH组在初冬感染较高水平的球虫，进而在翌年繁殖期获得较高球虫抵抗力有关，该结果提示，早期应激个体在当前高密度环境中的球虫感染可降低个体在翌年繁殖季节的感染，进而降低对繁殖的影响。以上结果表明，球虫是根田鼠肠道中的主要寄生物，E.wenrichi是球虫中的优势种，其感染参数存在时间动态，并受到宿主密度和年龄及繁殖的影响。早期应激与当前环境对球虫感染具有耦合效应。子代种群越冬后，在繁殖期E.wenrichi的感染结果进一步说明，根田鼠对其肠道寄生物的感染具有适应性。由此可见，球虫在根田鼠种群波动中可能具有重要性，需进一步研究球虫在根田鼠种群波动中的作用。
其他摘要	Parasites are common in small mammal populations, and play an important role in population regulations of small rodents. But the coupling effect of prenatal and current stress on intestinal parasites infecting small mammal in natural populations has not been reported. So researching the relationship between parasite and small mammal populations in nature will help us to understand and recognize the role of parasite in population regulation, and benefit for control harmful small mammal. In April of 2012, we established high density and low density enclosed parents’ populations of root voles (Microtus oeconomus) in Haibei Research Station of Alpine Meadow Ecosystem. In the middle of August of 2012, we established 4 progeny populations with F1 individuals born in parents’ populations. They are that (1) Prenatal context from low density, postnatal context from low density(LL); (2) Prenatal context from low density, postnatal context from high density(LH); (3) Prenatal context from high density, postnatal context from low density(HL); (4) Prenatal context from high density, postnatal context from high density (HH). To analyze the effects of treatments on parasite infection, we examined population parameter (population density and recruitment) by mark-recapture, and fecal corticosterone metabolic (FCM) concentrations and infection parameter (prevalence and intensity) by collecting fresh fecal. This is meaningful to further study the role of parasites in populations of root voles. Results are as follows: (1) Coccidian is the key intestinal parasite among parasites (coccidia, cestode and nematodes) and Eimeria wenrichi is the dominant species among the coccidia in root vole populations. We found that E.wenrichi infection significantly increased with time. In addition, E.wenrichi infection in juveniles in high density enclosures was higher than that in low density enclosures. E.ochrogasteri infection was higher in juveniles than that in adults. However, sex-related susceptibility was not found for coccidian species. (2) The prenatal and current stresses have a significant interactive effect on the infection of E.wenrichi, whose prevalence in HH was higher than that in LH and HL and E.wenrichi prevalence in LL was higher than that in LH and HL in different populations of offspring. However, reproduction of root voles has a significant on the infection of coccidian. (3) The effects of prenatal and current stresses on coccidian infection can’t be passed F2 of root voles. (4) The prevalence and intensity of E.wenrichi in different treatments had no difference in over winter populations of root voles. This is related to higher infection of coccidian before winter, and achieve more immune to parasite in next reproductive period. The result indicates that individuals of prenatal stress，they are infected by coccidian in current high density，can reduce infection and effects of coccidian on reproduction of root voles in next reproductive period. These results indicate that Coccidian is the key intestinal parasite among parasites (coccidia, cestode and nematodes) and E.wenrichi is a dominant species among the coccidian in root vole populations. Coccidian infection varied with time，and is effected by population density, age and reproduction of hosts. Prenatal stress and current context of high density have a coupling effect on coccidian infection to the root vole populations. The result of parasite infection of next reproductive period in over wintering populations of root voles further indicate that root voles on parasite infection is adaptive. Therefore, parasites may play an important role in population dynamic of root voles, and require future studying the effects of coccidian on the population dynamic of root voles.
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/4040
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	聂绪恒. 早期应激与当前环境对肠道寄生物感染根田鼠（Microtus oeconomus）的耦合效应[D]. 北京. 中国科学院研究生院,2014.

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