【Abstract】 Objective To understand the ectoparasite communities in a population of Eothenomys miletus in the surrounding areas of Erhai Lake and describe the importance of them in the medicinel and veterinary. Methods Investigation sites were randomly selected at different direction of surrounding areas of Erhai Lake in Yunnnan. Small mammals were captured by live traps with baits. The live traps were examined and the baits were changed each morning. Trapped small mammals were brought to the laboratory to identify according to their body shape, size and color, and some measurements such as body length, ear length and hind feet length, and ectoparasites were collected. Ectoparasites were identified under a microscope after mounting, clearity and desiccation. The constituent ratio (C), prevalence (P) and average ectoparasite abundance (A) were used to reflect the prevalence and density of ectoparasites. Non-parametric Mann-Whitney U-tests were used to test differences in the abundance and richness of ectoparasites between female and male hosts. Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body parameters of hosts. Results There were 916 E.miletus caught. Of which, a total of 756 were infested by ectoparasite, and the infestation rate was 83%. A total of 86 species of ectoparasite were collected, including 51 species of chigger mite, 23 species of gamasid mite, 7 species of flea and 5 species of sucking louse. Seventeen species were proved to be the main vectors of human disease. Conclusion There was very high diversity of ectoparasites parasitized on E.miletus, and some species had been reported to be associated with human disease. E.miletus could be a natural reservoir of plague bacilli, epidemic haemorrhagic fever (korean haemorrhagic fever) viruses and scrub typhus.

Objective To understand the species distribution of ectoparasitic chigger communities on small mammals in Yunnan province. Methods Mammals (the host of chiggers) were captured with mouse cage traps and bait in 16 counties (or cities) of Yunnan province. All the chiggers on two auricles of the hosts were made into specimens with Hoyer's medium and all the specimens were identified under microscope. Preston's lognormal distribution model was used to fit the species abundance. Results 6888 small mammal hosts were captured and 192 chigger species were collected, which belong to 21 genera, 3 subfamily of Trombiculidae. Leptotrombidium scutellare and L.sinicum were dominant chigger species. The species abundance distribution of chigger mites is successfully fitted to Preston's lognormal distribution model with the goodness of fit of 0.7975. Conclusion The species abundance distribution of chiggers on small mammals conforms to the lognormal distribution. Most chiggers species are the common species with middle levels of individuals, rare species take second place, while few species are dominant quantitatively.

Objective To study the structure of Chigger mite communities on small mammals in the surrounding areas of north Jinsha River in Yunnan.Methods The areas in different orientation surrounding north Jinsha River were selected as investigated spots.Small mammals were randomly captured with cage trap.Two auricles and hip 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 and hip 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 every species of the specimens of the chigger mites on the slides was finally identified under a microscope.A series of ecological methods about community structure diversity and similarity was involved in this paper.Results The captured 302 small mammals were identified as 16 species and 13 genera in 7 families.4550 individuals of Chigger mites were collected from the two auricles of 302 small mammal hosts and they were identified as 63 species and 12 genera in 3 subfamilies of Trombioulidae.The amount of six dominant Chigger mites species accounted for 75.68% of the total mites,which were Walchia ewingi, W.micropelta, Leptotrombidium sinicum, L.scutellare, Helenicula simena, L.scutellare.There were 4 main species of small mammal hosts,which richness indices were above 10,the highest reached 32.While the diversity indices of the 4 hosts were above 1 with the highest index 2.5732.The similarity indices of community structure of Chigger mites on the same species of host in different ecological surroundings were all above 0.9.Conclusion The community structure of Chigger mite are complicated with high diversity index in the surrounding areas of north Jinsha River in Yunnan.