【作者】 孙笑梅；

【导师】 郭宪国；

【作者基本信息】 大理学院 ， 病原生物学， 2012， 硕士

【摘要】 目的：(1)针对于动物分类上隶属啮齿目、鼠科的鼠类小型哺乳动物(小兽),按照不同的小兽种类,研究其体表寄生恙螨的种类组成、物种多样性、群落基本结构和种多度关系；(2)研究不同种类鼠科小兽宿主体表优势恙螨的空间分布型；(3)探讨云南省境内恙虫病主要媒介的宿主寄生及选择情况。材料与方法：(1)原始资料来源于郭宪国领导的课题组自2001-2010年对云南省境内20县(市)的野外现场抽样调查,这20个县(市)是根据云南省不同地理方位、地形地貌、气候与生态环境等特点选取的。(2)运用构成比(Dr)、物种丰富度指数(S)、Simpson优势度指数(D)、Shannon-Wiener多样性指数(H’)、群落均匀度(J’)感染率或染螨率(RM)、感染度或螨指数(IM)和生态优势度指数(C’)等分析鼠科小兽体表寄生的恙螨群落结构和多样性。(3)用聚块指数(m*/m)进行主要鼠科小兽体表寄生优势螨种的空间分布型研究。(4)运用生态位宽度指数(Shannon-Wiener指数和Simpson指数)及Pianka生态位重叠指数对鼠科小兽体表的主要恙螨生态位进行分析,用系统聚类分析法进行不同螨种间的生态位重叠群的划分。(5)运用Preston对数正态分布模型拟合种多度关系的理论分布曲线,并估测云南省鼠科小兽体表恙螨群落的恙螨总物种数。结果：(1)在云南省20县(市)境内共捕获鼠科小兽7757头,分类鉴定为啮齿目鼠科9属22种。从捕获的所有鼠科小兽体表(耳廓及外耳道)共采集到恙螨27042只,经分类鉴定,隶属于3亚科20属191种(不包括待定种);恙螨亚科14属142种19179只,其中,纤恙螨属82种13802只,其余13属恙螨60种5377只;背展恙螨亚科4属45种7813只；列恙螨亚科2属4种。21种恙螨的构成比较高,尤以小板纤恙螨、攸氏无前恙螨及微板无前恙螨突出。所捕获的小兽中,以齐氏姬鼠(7708只)为优势,构成比是20.61%。(2)云南省鼠科小兽及体表寄生的恙螨的数量和种类因海拔、地域的不同而有差异。海拔2000米以下区域,所捕获的小兽以黄胸鼠为主,所采集的恙螨以印度囊棒恙螨、攸氏无前恙螨、微板无前恙螨和地里纤恙螨为主：海拔2000米以上区域,小兽以齐氏姬鼠和褐家鼠为主,恙螨以小板纤恙螨为主。(3)云南省鼠科小兽体表寄生的恙螨物种多样性较高,对宿主的选择不严格,宿主特异性低,同一种恙螨可寄生多种宿主,同一种宿主体表可采集到多种恙螨。斯氏家鼠体表最多可寄生102种恙螨,其次是社鼠和黄胸鼠,均采集到89种恙螨。(4)作为我国恙虫病主要传播媒介的地里纤恙螨和小板纤恙螨,其宿主范围也比较广泛,其地理分布受海拔和生境等诸多因素的影响。地里纤恙螨的主要寄生宿主除了黄胸鼠外,有别的主要宿主。(5)21种主要恙螨中,密点纤恙螨的生态位宽度最宽,蒙大微恙螨的生态位宽度最低。大多数恙螨存在于几种小兽体表,所以生态位宽度值并不高。21种恙螨之间存在两两不同的生态位重叠,系统聚类结果显示,在λ=21处聚为3类。(6)云南省鼠科小兽体表寄生的恙螨物种多度分布呈现近似对数正态分布,并估测出鼠科小兽体表寄生恙螨的总物种数为365种。社鼠体表寄生的恙螨群落种多度分布呈现近似对数正态分布,并估测社鼠体表寄生的恙螨总物种数为170。结论：(1)云南省鼠科小兽体表寄生恙螨种类丰富,物种多样性很高,恙螨群落结构比较复杂。(2)云南省鼠科小兽体表寄生恙螨以小板纤恙螨、攸氏无前恙螨及微板无前恙螨占优势。(3)云南省鼠科小兽体表的小板纤恙螨在高海拔地区数量较多,地里纤恙螨在低海拔地区数量较多,云南可能并存多种恙虫病媒介恙螨。(4)云南省鼠科小兽体表的优势恙螨在主要小兽体表呈现聚集性分布。(5)云南省鼠科小兽体表寄生的多数恙螨呈现寄生宿主的广泛性及低特异性。生态位重叠程度较高,恙螨与小兽协同进化程度不高。(6)云南省鼠科小兽体表寄生恙螨群落种多度分布呈现近似对数正态分布,总物种数估测为365种。社鼠体表寄生的恙螨群落种多度分布亦呈现近似对数正态分布,总物种数估测为170种。更多还原

【Abstract】 Objectives:(1) To understand the species composition, species diversity, community structure and species abundance distribution of chigger mites on their rodent hosts in family Muridae (Rodentia).(2) To study the spatial distribution patterns of dominant chigger mites on some hosts’body surface.(3) To study the host specificity and host selection of some main chigger species associated with the transmission of scrub typhus in Yunnan Province.Materials and Methods:(1) The original data came from the field investigation in20locations of Yunnan Province from2001to2010. The field investigations were chosen according to different landscapes, geographical orientations, climate and environment, etc.(2) The community structure was illustrated by a series of parameters, including the constituent ratio (Dr), species richness (S), Simpson’s dominance index (D), Shannon-Wiener’s diversity index (H’),evenness (J’), mite infected rate (Rm) and mite index (IM).(3) The patch index (m*/m) was used to measure the spatial distribution pattern of dominant chigger mites on some hosts’ body surface.(4) Niche breadth (Shannon-Wiener index and Simpon index) and Pianka niche overlap index were used to study the niche overlaps between some main chigger mite species and hiearchical cluster analysis was used to classify the overlapping groups.(5) Preston’s logarithmic normal distribution was used to describe the theoretical distribution curve of species-abundance of chigger mites, and then estimated the total species number of chigger mites on small Rodents in Muridae (Rodentia) in Yunnan Province based on the distribution curve.Results:(1) A total of7757individuals of rodents (rats) in Muridae were captured in Yunnan Province and identified as22species in9genera.27042individuals of chigger mites were collected from the body surface of these rodent hosts and identified as191species,20genera in3subfamilies (not including unidentified species). Of these191species, there were142species (19179individuals) and14genera, which belong to subfamily Trombiculinae. Of subfamily Trombiculinae, there were82species (13802individuals) in genus Leptotrombidium and60species (5377individuals) in other13genera. In subfamily Gahrliepiinae, there were 45species (7813individuals) and4genera. In subfamily Leeuwenhoekiinae, there were4species (50individuals) and2genera. Of191chigger species, the constituent ratios of three dominant mite species, Leptotrombidium scutellare, Walchia ewingi and Walchia micropelta, were much higher than other species.7708individuals of Apodemus chevrieri were captured and they were considered as one dominant species of rodent hosts in this paper.(2) The altitude of the investigation areas had some influences on the distribution of rodent hosts and their ectoparasitic chigger mites in Yunnan province. In the areas below2000meters, the dominant rodent hosts was Rattus tanezumi (R. flavipectus) and the dominant chigger mites were Ascoschoengastia indica, Walchia ewingi, W. micropelta and Leptotrombidium deliense. In the areas above2000meters, however, the dominant hosts were Apodemus chevrieri, Rattus norvegicus while the dominant chigger species was Leptotrombidium scutellare.(3) Chigger mites of rodents in Yunnan Province have high species diversity but low host specificity.Not only one chigger mite can parasite one more hosts, but also one host can be found one more chigger mites.(4) The distribution of Leptotrombidium scutellare and L. deliense, which are the two main vector species in China, fluctuated in different latitude regions and habitats. Both these two mite species had a wide host range. Apart from some other rodent species, however, the main host of Leptotrombidium deliense was Raltus tanezumi.(5)The widest niche breadth is L. densipunctatum,the narrowest is Microtrombicula munda among total21main chigger mites species. Most chigger mites can parasite several rodents,so niche breadth is low. Most chigger mites have different niche overlap. The result of Hierachical analysis revealed that all21mite species be clusted into3categories.(6) The species abundance distribution of the chigger mite community was successfully fitted by a lognormal distribution model. Based on the theoretical curve of species abundance distribution, the total number species of the chigger mites was roughly estimated as365species, the same as Niviventer confucianus, the total number species was roughly estimated as170species.Conclusions:(1) The species diversity of chigger mites on rodent hosts in Yunnan Province is very high with a complicated structure.(2) Leptotrombidium scutellare, Walchia ewingi and Walchia micropelta are the dominant chigger species in Yunnan Province on hosts of Muridae.(3) Two main vector species of chigger mites, Leptotrombidium scutellare and Leptotrombidium deliense, coexist in Yunnan Province. The former (L. scutellare) mainly distributes in high altitude regions while the later (L. deliense) mainly in low altitude regions.(4) The distribution of chigger mites on main hosts of Muridae is assembled.(5) The host specifity of most chigger mites of hosts on Muridae is quite low with a wide host range. There is a high niche overlap,but low co-evolution on chigger mites.(6) The species abundance of chigger mite community conforms to lognormal distribution and the total species number of chigger mites is roughly estimated as365species. The same as Niviventer confucianus, the total number species is roughly estimated as170species.更多还原