Peng Pei-Ying, Guo Xian-Guo, Ren Tian-Guang, Song Wen-Yu, Dong Wen-Ge, Fan Rong
Vector Laboratory, Institute of Pathogens and Vectors, Dali University (Branch of Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention), Dali, Yunnan Province, 671000, People's Republic of China.
Parasitol Res. 2016 Sep;115(9):3605-18. doi: 10.1007/s00436-016-5127-x. Epub 2016 May 23.
Chigger mites are a large group of arthropods and the larvae of mites are ectoparasites. Some species of ectoparasitic mites (larvae) can be the transmitting vectors of tsutsugamushi disease (scrub typhus). Yunnan Province is located in the southwest of China with complicated topographic landform and high biodiversity, where there are five zoogeographical subregions. Rodents and some other small mammals were trapped and examined for ectoparasitic chigger mites in 29 investigation sites in Yunnan during 2001-2013. From 13,760 individuals and 76 species of small mammal hosts, we collected 274 species of mites, which were identified as comprising 26 genera in two families. The species diversity of chigger mites (274 species) in the present study were not only much higher than that from other provinces of China but also largely exceeded that recorded from other regions and countries in the world. Of the five zoogeographical subregions, both the species diversity and Shannon-Weiner's diversity of mites were the highest in subregion II (southern subregion of Hengduan Mountains) with middle altitudes and middle latitude. Both the species diversity of mites and Shannon-Wiener diversity index showed a parabolic tendency from the low altitude (<500 m) to the high altitude (>3500 m) along the vertical gradients with the peak occurring in the middle-altitude regions (2000-2500 m). Of four dominant hosts, the species richness of mites was highest on Eothenomys miletus (S = 165) and Shannon-Wiener diversity index was highest on Rattus norvegicus (H = 3.13). Along latitude gradients, species richness of chigger mites increased first and then decreased, peaking at 25° to 26° N with 193 mite species. The geographical location, complex topography, and landscape with diverse small mammal hosts in Yunnan Province have contributed to the extremely high species diversity of mites in the province. The large sampling size of small mammal hosts in a wide geographical scope within a long time span also made it possible to have collected so many species of chigger mites.
恙螨是一大类节肢动物，螨的幼虫是体外寄生虫。一些体外寄生螨（幼虫）可成为恙虫病（ scrub typhus）的传播媒介。云南省位于中国西南部，地形地貌复杂，生物多样性高，有五个动物地理亚区。2001年至2013年期间，在云南省的29个调查点对啮齿动物和其他一些小型哺乳动物进行了捕获，并检查其体外寄生恙螨。从13760只个体和76种小型哺乳动物宿主中，我们收集到274种螨，经鉴定它们分属于两个科的26个属。本研究中恙螨的物种多样性（274种）不仅远高于中国其他省份，也大大超过世界其他地区和国家的记录。在五个动物地理亚区中，螨的物种多样性和香农 - 维纳多样性在亚区II（横断山脉南部亚区，中海拔和中纬度）最高。沿着垂直梯度，螨的物种多样性和香农 - 维纳多样性指数从低海拔（<500米）到高海拔（>3500米）呈抛物线趋势，峰值出现在中海拔地区（2000 - 2500米）。在四种主要宿主中，螨的物种丰富度在大绒鼠上最高（S = 165），香农 - 维纳多样性指数在褐家鼠上最高（H = 3.13）。沿着纬度梯度，恙螨的物种丰富度先增加后减少，在北纬25°至26°达到峰值，有193种螨。云南省的地理位置、复杂地形以及有多样小型哺乳动物宿主的景观促成了该省螨的极高物种多样性。在长时间跨度内对广泛地理范围内的小型哺乳动物宿主进行大量采样，也使得有可能收集到如此多的恙螨物种。
