洞庭湖区鼠类群落的物种多样性分析

通过对洞庭湖区黑线姬鼠褐家鼠主害区桃源的害鼠群落调查,揭示了平原农田生态类型区、丘陵农林复合生态类型区和山区林农复合生态类型区及其不同生境的鼠类群落的物种多样性。在人类干扰程度最高的平原生态类型区,鼠类群落的优势种突出,优势集中性指数最高,丘陵生态区次之,而具有大片森林、受干扰较低的山区林农复合生态区,优势集中性指数最低。物种多样性Shannon—Weiner指数和均匀性指数亦显示同样的规律：适度干扰的山区复合生态区的多样性指数最高,均匀性最好,丘陵生态区居中,平原生态区最低。不论何种生态类型区,农田生境鼠类群落的优势种都较突出,优势集中性指数也较高,群落多样性和均匀性较低;林地生境的优势集中性有较大下降,山区林地内的鼠种比丘陵区要多,优势集中性指数也较低,多样性指数和均匀度都有提高。林缘农田在同一生态类型不同生境内优势集中性最低、多样性指数和均匀性最高。比较不同生境鼠类群落的相似性,最不相似的群落是农田与受人类干扰较小的森林。这些现象说明人类的社会生产活动使害鼠群落的物种多样性降低、优势度下降、优势种突出、均匀性降低,形成了只利于少数几个种群栖息和生产发展的环境,最终导致少数种群的暴发,形成危害。但适度干扰能提高物种多样性。     

中国云南人间鼠疫流行区十种小兽体表蚤类群落的比较(英文)

本文将某一种小兽 (小型哺乳动物 )宿主体表的全部蚤作为一个特定的蚤类群落 ,在此基础上运用模糊聚类分析方法对云南人间鼠疫流行区 10种小兽体表的蚤类群落之间的相似性进行了比较。研究结果表明 ,在动物分类上比较接近的、隶属同一属 (鼠属 )的黄胸鼠、大足鼠和斯氏家鼠体表 3种蚤类群落之间的相似性较大 ,在模糊聚类的谱系图上明显聚为一类。动物分类上距离较远、隶属不同属的微尾、臭、灰麝、中华姬鼠、滇绒鼠、社鼠和锡金小鼠体表的 7种蚤类群落之间的相似性较小。结果提示 ,宿主因素可能是影响体表寄生蚤群落之间相似性大小的一个主要因子 ,当宿主在动物分类上彼此接近时 ,其体表寄生蚤群落的相似程度就比较高 ,当宿主在动物分类上距离较大时 ,其体表蚤类群落的相似程度就比较低。本文中不同属小兽体表寄生蚤类形成了不同的群落类型。     

茶园间作不同绿肥对节肢动物群落结构和多样性的影响

【目的】研究在茶园中合理间作绿肥对茶园节肢动物群落结构和多样性的影响。【方法】本文在茶园中分别设间作铺地木兰+罗顿豆、圆叶决明+白三叶、白三叶+平托花生3种不同绿肥组合处理,并设不间作绿肥、常规除草的茶园为对照。【结果】间作不同绿肥均能提高茶园节肢动物群落的物种丰富度和群落多样性,提高茶园捕食性天敌昆虫、蜘蛛和寄生性天敌在茶园冠层群落的比率;不同处理茶园冠层节肢动物Shannon-wiener多样性指数(H)、Simpson指数(D)和均匀度指数变化趋势基本一致;茶冠层的节肢动物群落多样性指数在4类不同处理茶园间差异显著;间作绿肥增加了茶园的生物多样性,4类不同处理茶园茶冠层群落相似性系数在0.741~0.892之间,表明4类不同处理茶园冠层群落在物种组成上有较高的相似性。4类不同处理茶园害虫与天敌两类群功能团的丰盛度之间成显著的正相关,表明天敌对害虫的空间数量跟随效应强,主要表现为二者数量间的相互作用。灰色关联度分析表明在4类不同处理茶园中的群落节肢动物物种数/个体数、天敌物种数/害虫物种数、害虫丰富度与多样性指数和均匀度指数的关联系数较高,反应了群落的多样性和稳定性。【结论】间作增强了茶园群落的生物多样性,提高害虫天敌的种类和个体数,有利有效发挥天敌对有害生物的生态控制。     

闽东山区鼠类群落的空间配置和结构的研究

1984年3月-1985年1月对闽东山区鼠类群落的调查结果表明,根据鼠种类和数量组成,该区可划分为针毛鼠+社鼠;黑线姬鼠+黄毛鼠、黄毛鼠+黑线姬鼠;褐家鼠+小家鼠+黄胸鼠等4个鼠类群落。不同鼠类群落的组成和数量有不同的季节变化。本文比较了不同鼠类群落的多样性指数、均匀性指数和相对生物量。     

云南省农耕区小型兽类群落结构及分布格局

为了解云南省农耕区小型兽类群落结构及空间分布特征,根据云南不同经纬度、海拔等自然环境条件,于2010年8月—2018年4月,选取云南省25个调查样区中104块农耕地,采用铗夜法开展小型兽类调查,运用群落生态学指标对农耕区小型兽类的群落特征和沿环境梯度的空间分布进行研究.结果表明: 共捕获小型兽类3240头,隶属4目9科21属42种,其中啮齿目最多,以齐氏姬鼠和黄胸鼠为代表.25个样区聚类为三大类.小兽在纬度和垂直分布上类似,低纬度和低海拔范围的种类相对较少,以家鼠属和小鼠属为主,而高纬度和高海拔地区以姬鼠属、白腹鼠属和绒鼠属为主.小兽物种多样性指数随着海拔的增加呈现先增后降的单峰分布格局,峰值出现在中海拔地区;经度水平分布上,小兽多样性指数呈V型分布格局,在98°—99° E最高;而纬度水平上,小兽多样性指数由南到北总体呈上升趋势.广义可加模型(GAM)分析表明,各因子对农耕区小型兽类多样性指数分布格局的影响程度为经度>海拔>纬度.相似性分析表明,相邻梯度带之间小兽群落结构为中等相似,相似性最高出现在中海拔带、中纬度带、低经度带之间,不同梯度带距离越远,小兽相似性越低.云南省农耕区小兽群落结构在不同维度上存在较高的空间异质性,物种多样性的地理分布随环境梯度变化呈现出不同的分布格局.     

云南居民区鼠类体外寄生蚤物种多样性调查

【目的】了解云南居民区鼠类寄生蚤的群落结构和空间分布特征。【方法】根据云南不同经纬度、 海拔等自然环境条件, 于2007年4月-2012年11月, 选取云南17个县(市) 居民区作为样区, 系统开展鼠类体外寄生蚤的调查, 运用群落结构指标对居民区鼠类寄生蚤的群落特征和沿环境梯度的空间分布进行研究。【结果】结果显示： 在调查的17个县(市)室内共检获鼠类体外寄生蚤521头, 隶属4科7亚科9属12种。居民区寄生蚤的纬度和垂直分布类似, 低纬度和低海拔范围的种类相对较少, 印鼠客蚤和缓慢细蚤是室内寄生蚤的优势种。相对纬度和海拔较高的区域, 居民区寄生蚤种类增多, 但优势种不突出; 在经度水平分布上, 蚤种类于99°~101°E经度带形成一个高峰, 室内寄生的优势种印鼠客蚤和缓慢细蚤几乎在所有经度带都可见到分布, 显示了较宽的生态幅。另外, 居民区寄生蚤物种丰富度和多样性指数水平分布（纬度）和垂直分布呈现为单峰格局, 总体显示随着纬度和海拔的升高, 先升高后降低的分布特征, 而在另一个水平分布（经度）, 则呈现由西向东呈递减的趋势。【结论】研究认为, 云南居民区蚤类的空间分布表现为独特的地理区域特征, 气候环境、 森林植被和人类生活生产方式通过影响蚤类栖息生境来影响蚤类的分布。     

广西生态茶园和普通茶园的节肢动物群落结构和稳定性分析

为了解广西生态茶园与普通茶园节肢动物群落结构特点及其稳定性,本文采用Shannon-Wiener多样性指数（H′）、群落物种优势度指数（D）、丰富度指数（J）、物种均匀度指数（E）等分析了茶园节肢动物群落的多样性结构,应用群落相似度指数对生态茶园和普通茶园节肢动物的群落相似性进行了分析,用灰色关联度方法综合分析多样性指数与优势度、均匀度等6个特征参数间关系的密切程度。结果表明,在广西茶园节肢动物共34种,其中害虫（螨）17种,优势种群是：小贯小绿叶蝉Empoasca onukii Matsuda、茶蓟马Scirtothrips dorsalis Hood、蚜虫、白粉虱Trialeurodes vaporariorum Westwood;天敌8种,优势种群是：棕管巢蛛Clubiona japonicola Boeset Str.、八斑球腹蛛Theridion octomaculatum Boes. et Str.、异色瓢虫Harmonia axyridis(Pallas);中性昆虫9种,优势种群是：蚊虫、蚁类。多样性指数、群落均匀度指数与物种优势度在生态茶园比普通茶园高。生态茶园的群落稳定性比普通茶园的强。不同茶园间的群落相似性指数q在0.444~0.9355之间,群落间相似性关系在中等不相似与极度相似之间。与多样性指数密切相关的前3位群落特征参数依次是群落物种优势度、益害物种的个体数比、丰富度,其中关系最密切的特征参数是群落物种优势度。研究结果为茶园害虫的综合防控提供了理论依据。     

黄土丘陵区沙棘群落封育过程中物种多样性动态

对黄土丘陵区子午岭不同封育年限沙棘群落的高等植物多样性特征进行了初步分析。结果表明：不同封育阶段沙棘群落灌木层和草本层的物种多样性指数表现出大致相同的趋势,即草本层>灌木层。同一层次的物种多样性指数D和H′虽然数值不同,但在不同封育阶段沙棘群落有基本一致的趋势,灌木层物种多样性指数基本上随封育时间的增加而增加;草本层多样性指数在荒草地阶段较高,其他阶段的沙棘群落随封育时间的增加而减少。随着群落封育,群落相似性增加。总体上,随着沙棘群落的封育,不同科属的植物种类在增加,群落生态优势度增加,群落趋向稳定。采取封禁措施,减少人为干扰,是沙棘群落封育的有效途径。     

都江堰地区小型哺乳动物群落与生境类型关系的初步研究

于2000年10月底至11月初,对都江堰地区中亚热带常绿阔叶林带不同生境类型中小型哺乳动物群落的多样性变化进行了初步研究。其捕获小型哺乳动物12种,其中啮齿目（Rodentia）鼠科（Muridae）10种,食虫目（Insce-tivora）JuQin科（Soricidae）2种,总捕获率为10.67%,在所调查的7个生境中,以干扰较轻的次生林中小型哺乳动物物种多样性指数（1.8438）和均匀度（0.9475）最高,灌丛、次生林1、原生林和弃耕地均有较高的多样性指数,农田受人类的干扰最严重,物种单一,优势度（0.5703）明显;柳杉林中的多样性指数（1.3380）和均匀度(0.8313）均较低。但原生林的物种多样性指数（1.4305）略低于次生林（1.8475和1.4610）,灌丛（1.6398）和弃耕地(1.6566）。根据不同生境内群落相似性指数进行系统聚类,7个生境在相似性指数0.0952处全部聚合在一起,灌丛、原生林和次生林中主要分布有森林型小型哺乳动物,聚为一类,为森林群落型;柳杉林和农田以大足鼠（Rattus nitidus）为优势种,聚为一类,为农田群落型;弃耕地一方面由于群落多样性指数较高（1.6566）,另一方面其农田型小型哺乳动物仍占较高比例（46.67%）,所以在聚类图中另成一类,为农林交错型。结果表明,人类活动过度干扰的生境（如农田、柳杉林）多样性指数最低,适度干扰的生境（如次生林、灌丛、弃耕地）多样性指数最高,干扰较少的生境（如原生林）多样性指数略低。     

漯河地区农田灯下蛾类群落结构和优势蛾生态位分析

为明确农田生境灯下蛾类群落结构和优势蛾的生态位特点,2017-2021年在漯河市郊区农田利用虫情测报灯对蛾类进行了逐日监测分析。结果表明,5年共诱集蛾类昆虫11科121种150 861头,统计得到个体数量（N)、物种丰富度(S)、群落多样性指数(H)、相似性系数(Cs)、生态位宽度（Bi）和生态位重叠(Cij)等相关群落数据参数。3-11月农田灯下蛾类个体数量、物种丰富度和群落多样性指数,均随时间呈先增加后减小的趋势;不同月份间的群落相似性指数差异较大。年度优势蛾为东方黏虫M. separata、棉铃虫Helicoverpa armigera和甜菜夜蛾Spodoptera exigua 3种。月度优势蛾共9种,其中亚洲玉米螟Ostrinia furnacalis和棉铃虫的生态位宽度最大0.4434和0.4002,东方黏虫最小（0.1811）;棉铃虫和甜菜叶螟Hymenia recurvalis与其余8种优势蛾的生态位重叠指数均较大,而东方黏虫和其余优势蛾的生态位重叠指数均较小。研究结果为开展蛾类监测预警和有效防治提供参考数据。     

Ecological characteristics of flea species relate to their suitability as plague vectors

The ability of vector-borne diseases to persist and spread is closely linked to the ecological characteristics of the vector species they use. Yet there have been no investigations of how species used as vectors by pathogens such as the plague bacterium differ from closely related species that are not used as vectors. The plague bacterium uses mammals as reservoir hosts and fleas as vectors. The ability of different fleas to serve as vectors is assumed to depend on how likely they are to experience gut blockage following bacterial multiplication; the blockage causes fleas to regurgitate blood into a wound and thus inject bacteria into new hosts. Beyond these physiological differences, it is unclear whether there exist fundamental ecological differences between fleas that are effective vectors and those that are not. Here, using a comparative analysis, we identify clear associations between the ability of flea species to transmit plague and their ecological characteristics. First, there is a positive relationship between the abundance of flea species on their hosts and their potential as vectors. Second, although the number of host species exploited by a flea is not associated with its potential as a vector, there is a negative relationship between the ability of fleas to transmit plague and the taxonomic diversity of their host spectrum. This suggests a correlation between some ecological characteristics of fleas and their ability to develop the plague blockage. The plague pathogen thus uses mainly abundant fleas specialized on a narrow taxonomic range of mammals, features that should maximize the persistence of the disease in the face of high flea mortality, and its transmission to suitable hosts only. This previously unrecognized pattern of vector use is of importance for the persistence and transmission of the disease.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

Prevalence of Yersinia pestis in rodents and fleas associated with black-tailed prairie dogs (Cynomys ludovicianus) at Thunder Basin National Grassland, Wyoming

Rodents (and their fleas) that are associated with prairie dogs are considered important for the maintenance and transmission of the bacterium (Yersinia pestis) that causes plague. Our goal was to identify rodent and flea species that were potentially involved in a plague epizootic in black-tailed prairie dogs at Thunder Basin National Grassland. We collected blood samples and ectoparasites from rodents trapped at off- and on-colony grids at Thunder Basin National Grassland between 2002 and 2004. Blood samples were tested for antibodies to Y. pestis F-1 antigen by a passive hemagglutination assay, and fleas were tested by a multiplex polymerase chain reaction, for the presence of the plague bacterium. Only one of 1,421 fleas, an Oropsylla hirsuta collected in 2002 from a deer mouse, Peromyscus maniculatus, tested positive for Y. pestis. Blood samples collected in summer 2004 from two northern grasshopper mice, Onychomys leucogaster, tested positive for Y. pestis antibodies. All three positive samples were collected from on-colony grids shortly after a plague epizootic occurred. This study confirms that plague is difficult to detect in rodents and fleas associated with prairie dog colonies, unless samples are collected immediately after a prairie dog die-off.     

Flea-Associated Bacterial Communities across an Environmental Transect in a Plague-Endemic Region of Uganda

The vast majority of human plague cases currently occur in sub-Saharan Africa. The primary route of transmission of Yersinia pestis, the causative agent of plague, is via flea bites. Non-pathogenic flea-associated bacteria may interact with Y. pestis within fleas and it is important to understand what factors govern flea-associated bacterial assemblages. Six species of fleas were collected from nine rodent species from ten Ugandan villages between October 2010 and March 2011. A total of 660,345 16S rRNA gene DNA sequences were used to characterize bacterial communities of 332 individual fleas. The DNA sequences were binned into 421 Operational Taxonomic Units (OTUs) based on 97% sequence similarity. We used beta diversity metrics to assess the effects of flea species, flea sex, rodent host species, site (i.e. village), collection date, elevation, mean annual precipitation, average monthly precipitation, and average monthly temperature on bacterial community structure. Flea species had the greatest effect on bacterial community structure with each flea species harboring unique bacterial lineages. The site (i.e. village), rodent host, flea sex, elevation, precipitation, and temperature also significantly affected bacterial community composition. Some bacterial lineages were widespread among flea species (e.g. Bartonella spp. and Wolbachia spp.), but each flea species also harbored unique bacterial lineages. Some of these lineages are not closely related to known bacterial diversity and likely represent newly discovered lineages of insect symbionts. Our finding that flea species has the greatest effect on bacterial community composition may help future investigations between Yersinia pestis and non-pathogenic flea-associated bacteria. Characterizing bacterial communities of fleas during a plague epizootic event in the future would be helpful.     

Modeling plague persistence in host-vector communities in California

Plague is an enzootic disease in the western United States, even though long-term persistent infections do not seem to occur. Enzootic persistence may occur as a function of dynamic interactions between flea vectors and transiently infected hosts, but the specific levels of vector competence, host competence, and transmission and recovery rates that would promote persistence and emergence among wild hosts and vectors are not known. We developed a mathematical model of enzootic plague in the western United States and implemented the model with the following objectives: 1) to use matrix manipulation within a classic susceptible-->infective-->resistant-->susceptible (SIRS) model framework to describe transmission of the plague bacterium Yersinia pestis among rodents and fleas in California, 2) to perform sensitivity analysis with model parameters and variables to indicate which values tended to dominate model output, and 3) to determine whether enzootic maintenance would be predicted with realistic parameter values obtained from the literature for Y. pestis in California rodents and fleas. The model PlagueSIRS was implemented in discrete time as a computer simulation incorporating environmental stochasticity and seasonality, by using matrix functions in the computer language R, allowing any number of rodent and flea species to interact through parasitism and disease transmission. Sensitivity analysis indicated that the model was sensitive to flea attack rate, host recovery rate, and rodent host carrying capacity but relatively insensitive to changes in the duration of latent infection in the flea, host and vector competence, flea recovery from infection, and host mortality attributable to plague. Realistic parameters and variable values did allow for the model to predict enzootic plague in some combinations, specifically when rodent species that were susceptible to infection but resistant to morbidity were parasitized by multiple poorly competent flea species, including some that were present year-round. This model could be extended to similar vectorborne disease systems and could be used iteratively with data collection in sylvatic plague studies to better understand plague persistence and emergence in nature.     

云南省玉龙鼠疫疫源地野外鼠形动物寄生蚤丰盛度影响因素分析

【目的】分析云南省玉龙鼠疫疫源地野外鼠形动物寄生蚤丰盛度的影响因素。【方法】选取云南省玉龙鼠疫疫源地3个海拔区域,按4个季节进行野外捕鼠,捕获的鼠形动物用梳检法收集体表寄生蚤并在显微镜下分类鉴定。通过实际测量和实地观察相结合的方式收集潜在影响鼠形动物寄生蚤丰盛度的因素包括鼠形动物特征变量指标(如种类、年龄、性别、体长、体重)、环境和气象因子(如海拔、季节)等数据。采用EpiData 3.02软件建立数据库,在R软件下使用跨栏负二项分布回归分析鼠形动物寄生蚤丰盛度的影响因素。【结果】从捕获的884只鼠形动物中检获寄生蚤9种484头,以特新蚤指名亚种、方叶栉眼蚤、无值大锥蚤、云南栉眼蚤为主(86.16%)。回归分析显示： 2 700-3 000 m和3 000 m以上海拔鼠形动物染蚤概率较2 400-2 700 m分别增加1.27和3.72倍;湿度高于70%时,鼠形动物染蚤概率较湿度≤70%时减少41%;与齐氏姬鼠的染蚤概率相比,中华姬鼠的染蚤概率降低50%,大绒鼠的染蚤概率增加79%;体长超过104 mm的鼠形动物染蚤概率较体长≤104 mm的鼠形动物染蚤概率增加76%;气温高于15℃时,鼠形动物染蚤数量较温度≤15℃时降低67%;成年鼠形动物的染蚤数量较未成年鼠形动物的染蚤数量增加2.25倍;与春季相比,夏季的染蚤数量增加2.00倍,秋季的染蚤概率减少48%,冬季的染蚤概率和染蚤数量分别增加1.44和1.06倍。【结论】玉龙鼠疫疫源地野外鼠形动物寄生蚤以特新蚤指名亚种、方叶栉眼蚤、无值大锥蚤、云南栉眼蚤为优势蚤种。鼠形动物寄生蚤丰盛度与海拔、季节、气温、湿度等环境气象因子及鼠形动物种类、体长、年龄等鼠形动物特征变量密切相关。     

Seasonal patterns of rodents, fleas and plague status in the Western Usambara Mountains, Tanzania

Field and commensal rodents were live-trapped at three villages in an active focus of plague (Yersinia pseudotuberculosis pestis) in Lushoto District, Western Usambara Mountains, Tanga Region, Tanzania, from December 1983 to November 1984. Their flea ectoparasites were collected, identified and counted. The rodent carcasses were serologically examined for specific plague antibodies and antigens, and bacteriologically examined for bipolar staining bacilli. A total of 1758 traps were set during the 12-month period and 924 animals were caught. From these, 1037 fleas were collected. Rattus rattus (L.), Praomys natalensis (Smith) and Lophuromys flavopunctatus Thomas comprised the largest proportions of the rodent population, while Dinopsyllus lypusus Jordan & Rothschild, Ctenophthalmus calceatus Waterston and Xenopsylla brasiliensis (Baker) were the dominant flea species. Rodents were most abundantly trapped during December and January. Flea indices were highest from December to May. Human plague was most active from November to March. Rodents contained plague antibodies every month except May and July, with a peak in September. Plague antigens and bipolar bacilli were detected in rodent organs during January-April. From the product of abundance and infection rate, the most prevalent rodent hosts of plague appeared to be R. rattus, Otomys angoniensis Wroughton, P. natalensis and Pelomys fallax (Peters). Continuous integrated control of rodents and fleas was recommended, reinforced by quarantine and maintenance of a surveillance service for clinical detection, diagnosis and treatment of patients in the plague endemic area.     

Geographic variation in rodent-flea relationships in the presence of black-tailed prairie dog colonies

We characterized the relationship between fleas and their rodent hosts in the presence of prairie dog colonies and compared them to adjacent assemblages away from colonies. We evaluated the rodent-flea relationship by quantifying prevalence, probability of infestation, flea load, and intensity of fleas on rodents. As prairie dog burrows provide refugia for fleas, we hypothesized that prevalence, flea load, and intensity would be higher for rodents that are associated with black-tailed prairie dog colonies. Rodents were trapped at off- and on-colony grids, resulting in the collection of 4,509 fleas from 1,430 rodents in six study areas. The rodent community composition varied between these study areas. Flea species richness was not different between prairie dog colonies and the surrounding grasslands (p = 0.883) but was positively correlated with rodent species richness (p = 0.055). Prairie dog colonies did not increase the prevalence of fleas (p > 0.10). Flea loads on rodents did not vary between off- and on-colony grids at three of the study areas (p > 0.10). Based on the prevalence, infestation rates, and flea loads, we identified Peromyscus maniculatus, Onychomys leucogaster, and two Neotoma species as important rodent hosts for fleas and Aetheca wagneri, Orchopeus leucopus, Peromyscopsylla hesperomys, Pleochaetis exilis, and Thrassisfotus as the most important fleas associated with these rodents. Prairie dog colonies did not seem to facilitate transmission of fleas between rodent hosts, and the few rodent-flea associations exhibited significant differences between off- and on-colony grids.     

Prairie dog presence affects occurrence patterns of disease vectors on small mammals

Wildlife disease is recognized as a burgeoning threat to imperiled species and aspects of host and vector community ecology have been shown to have significant effects on disease dynamics. The black‐tailed prairie dog is a species of conservation concern that is highly susceptible to plague, a flea‐transmitted disease. Prairie dogs (Cynomys) alter the grassland communities in which they exist and have been shown to affect populations of small rodents, which are purported disease reservoirs. To explore potential ecological effects of black‐tailed prairie dogs on plague dynamics, we quantified flea occurrence patterns on small mammals in the presence and absence of prairie dogs at 8 study areas across their geographic range. Small mammals sampled from prairie dog colonies showed significantly higher flea prevalence, flea abundance, and relative flea species richness than those sampled from off‐colony sites. Successful plague transmission likely is dependent on high prevalence and abundance of fleas that can serve as competent vectors. Prairie dogs may therefore facilitate the maintenance of plague by increasing flea occurrence on potential plague reservoir species. Our data demonstrate the previously unreported ecological influence of prairie dogs on vector species assemblages, which could influence disease dynamics.     

Fleas of Small Mammals on Reunion Island: Diversity,Distribution and Epidemiological Consequences

The diversity and geographical distribution of fleas parasitizing small mammals have been poorly investigated on Indian Ocean islands with the exception of Madagascar where endemic plague has stimulated extensive research on these arthropod vectors. In the context of an emerging flea-borne murine typhus outbreak that occurred recently in Reunion Island, we explored fleas'' diversity, distribution and host specificity on Reunion Island. Small mammal hosts belonging to five introduced species were trapped from November 2012 to November 2013 along two altitudinal transects, one on the windward eastern and one on the leeward western sides of the island. A total of 960 animals were trapped, and 286 fleas were morphologically and molecularly identified. Four species were reported: (i) two cosmopolitan Xenopsylla species which appeared by far as the prominent species, X. cheopis and X. brasiliensis; (ii) fewer fleas belonging to Echidnophaga gallinacea and Leptopsylla segnis. Rattus rattus was found to be the most abundant host species in our sample, and also the most parasitized host, predominantly by X. cheopis. A marked decrease in flea abundance was observed during the cool-dry season, which indicates seasonal fluctuation in infestation. Importantly, our data reveal that flea abundance was strongly biased on the island, with 81% of all collected fleas coming from the western dry side and no Xenopsylla flea collected on almost four hundred rodents trapped along the windward humid eastern side. The possible consequences of this sharp spatio-temporal pattern are discussed in terms of flea-borne disease risks in Reunion Island, particularly with regard to plague and the currently emerging murine typhus outbreak.