云南省大理洱海周边地带小兽体表恙螨群落结构

Community Structure of Chigger Mites on Small Mammals in the Surrounding Areas of Erhai Lake in Dali of Yunnan

目的了解大理洱海周边地带小兽体表恙螨寄生状况、恙螨物种多样性及群落结构特点。方法选择云南省大理洱海周边的不同地理方位作为野外抽样调查地点,用鼠笼(夹)加食饵诱捕小兽。以小兽耳窝作为固定采集部位,用手术刀片刮取耳窝的全部恙螨,70%酒精保存,Hoyer’s液封片后于显微镜下鉴定螨种。群落结构用丰富度(S)、ShannonWiener多样性指数(H′)、均匀度(J′)及优势度指数(C′)描述。结果捕获小兽3313只,经鉴定隶属7科14属21种。从3313只小兽双侧耳窝共采获恙螨56150只,经鉴定隶属3亚科13属109种。8种优势螨种占全部恙螨的74.42%。多数小兽体表恙螨种类丰富(8种以上),最多达58种。多数恙螨种类可同时寄生于不同宿主(5种以上),最多可寄生15种小兽。优势螨种在相应宿主寄生其染螨率(2.06%～59.02%)和螨指数(0.4627～68.5606)差异很大。在17种主要小兽中,有13种小兽体表恙螨群落的物种丰富度超过10,最高可达58;有15种小兽体表恙螨群落的多样性指数超过1,最高达2.5834。结论大理洱海周边地带小兽体表恙螨寄生普遍,恙螨物种多样性高、群落结构比较复杂。多数恙螨的宿主范围广泛,宿主特异性较低。

Objective To understand the distribution of chigger mites on the body surface of small mammals,together with the species diversity and community structure of the chigger mites, in the surrounding area of Erhai Lake in Dali of Yunnan,China. Methods Different oriented areas surrounding the Erhai Lake in Dali were selected as investigated spots. Small mammals were randomly captured with baited mouse cages. Two auricles of every small mammal host were chosen as a fixed site for collecting chigger mites. All the chigger mites on the surface of two auricles were scraped off by a bistoury at first and then preserved in 70 % of ethanol. Hoyer＇s medium was used to mount the chigger mites onto glass slides and the specimens of the chigger mites on the slides were finally identified into species under a microscope. Richness （S）, Shannon-Wiener diversity index （H＇） and dominance index （C＇） were adopted to measure the community structure of chigger mites on small mammals. Results The captured 3 313 small mammals were identified as 21 species and 14 genera in 7 families. 56 150 individuals of chigger mites were collected from the two auricles of 3 313 small mammal hosts and then they were identified as 109 species and 13 genera in 3 subfamilies of Trombiculidae. The individuals of eight dominant chigger mite species account for 74.42% of the total mites. Most small mammals host have abundant chigger mites （more than eight species of chigger mites） on their body surface （exactly auricle surface） and the highest one reaches 58 mite species. Most species of chigger mites can parasitize different species of small mammals hosts simultaneously （more than five host species at least） and the highest one reaches 15 host species. The infestation rate and the mite index of dominant chigger mites on their corresponding hosts vary from 2.06 % to 59.02 % and from 0. 462 7 to 68. 560 6 respectively. Of 17 main species of small mammal hosts, the richness （S） of chigger mite community on 13 host species is beyond 10 and the highest S reaches 58 while the diversity index on 15 host species is beyond 1 with the highest H＇ = 2. 583 4. Conclusion The chigger mite parasitism on small mammals is very common in the surrounding area of Erhai Lake in Dai pf Yunnan. The species of chigger mites are very abundant in the area and their community structure is complicated. Most chigger mite species have abundant small mammal hosts with low host specificity.