【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 investigate the basic information of sucking lice on the body surface of Eothenomys miletus (a dominant species of wild rats in Yunnan), including the louse species constitution and distribution, the dominant species of louse and their spatial pattern, the sex ratio and the community structure, etc. Methods E.miletus (the host of lice) was captured alive with a mouse trap in 17 counties (or towns) of Yunnan. All the lice on the body surface of the hosts were completely collected. Richness( S), diversity index( H′), evenness( J′) and dominance index( C′) were used to illustrate the community structure of sucking lice on the hosts according to Shannon-Wiener's method. Disperse coefficient( C), Cassie index( C_A), clumping index(I) and patch index(m/m) were adopted to measure the spatial distribution pattern of sucking lice. Results 1169 individuals of E.miletus were captured only in five counties (towns). Only six species of sucking lice (3528 individuals) were collected from the body surface of 1169 rats hosts (E.miletus). Both the richness and diversity index of sucking louse were very low. Hoplopleura edentula was the dominant species with 99.46% of relative dominance(D_r). The dominant louse species, H.edentula, showed an aggregation spatial distribution among the different individuals of the rat host. Male and female adults of H.edentula accounted for 81.62% of the whole development stages. The sex ratio of female/male in the dominant louse species was 1.53. Conclusion The sucking louse variety on E.miletus is very singularity and its community structure is also very simple. The distribution of H.edentula, a dominant louse species on E.miletus, is an aggregation pattern with more female adults.

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 investigate the community structure of fleas on Eothenomys miletus, together with the distribution of species-abundance and the relation of species-plots. Methods 19 counties (towns) in Yunnan province of China were selected as investigation spots. Flea specimens were collected from the body surface of every rodent. Every flea was finally identified into species under a microscope. All the fleas on Eothenomys miletus were defined as one community unit. Richness( S), Shannon-Wiener's diversity index( H′), evenness( J′) and dominance index( C′) were adopted to measure the community structure of fleas. Results 2248 fleas were collected from the body surface of 1295 rodents ( Eothenomys miletus). All the fleas were identified as 10 species belong to 7 genera of 3 families. Of 10 flea species, 2 main flea species accounts for 96.66% of the total specimens. The distribution of species-abundance shows that there are 3 species with only one individual and the individuals of 2, 4, 5, 16, 45, 121 and 2052 correspond to only one species in the flea community. The species-plot relationship shows that flea species increase with the increase of mouse plots(samples). Conclusion Eothenomys miletus can host several species of fleas, but most flea species are rare ones and they have not established a stable parasitic relationship with their host. Few flea species are dominant ones with abundant individuals.

Objective To understand species composition of gamasid mites on the body surface of Rattus flavipectus(a dominant species of domestic rats in Yunnan,China) and species diversity.Methods Twenty-five counties(towns) in Yunnan province were chosen to investigate the ectoparasitic gamasid mites on the body surface of R.flavipectus.All the individuals of R.flavipectus were randomly captured by mouse-traps and the gamasid mites on the body surface of R.flavipectus were all collected.Every individual of the gamasid mites was mounted on a glass slide after the dehydration and clarification in a conventional way.The mounted specimens of the gamasid mites were finally identified under a microscope.Results(18 250) gamasid mites were collected from the body surface of(3765) captured rats R.flavipectus and all the mites were identified as 40 species of 17 genera in 9 families.Of the 40 species of gamasid mites,three gamasid mite species(Laelaps nuttalli, L.echidninus and O.rnithonyssus bacoti were the dominants. L.nuttalinushas(10 667) individuals collected((58.45%)) while L.echidninus (5124)((28.08%)) and O.bacoti(1286)((7.05%)).37 species of gamasid mites are found in the southwest mountainous subregion in zoogeography with three dominant species, L.nuttalli((51.74%)), L.echidninus((29.74%)) and O.bacoti((11.40%)).In comparison with the species in the southwest mountainous subregion of Yunnan,less species of the mites(25 species) are collected in the southern mountainous subregion of Yunnan with two dominant mite species, L.nuttalli((64.35%)) and L.echidninus((26.61%)).Conclusion The ectoparasitic gamasid mite species on R.flavipectus in Yunnan province are very abundant and the species compositions of the gamasid mites are different in different zoogeographical regions.

Objective To understand the species composition,species distribution,the dominant species and their spatial pattern of ectoparasitic chigger mites on Rattus flavipectus(a dominant species of rats in Yunnan,China).Methods R.flavipectus(the host of mite) was captured with cage trap method in 16 counties(or towns) of Yunnan.All the mites on the two auricles surface of the hosts were completely collected,made into specimens and then identified under a microscope.The patch index (m*/m) was adopted to judge the spatial distribution patterns of the dominant chigger mite species among the different individuals on their rat hosts R.flavipectus. Results 725 individuals of R.flavipectus were captured only in 13 ones of those 16 counties(towns).(2 710) chigger mites(belonging to 3 subfamily,10 genus,42 species) were collected from the auricles(body surface) of 725 rat hosts R.flavipectus with high mite infection rate and mite index.There are four dominant mite species: Ascoschoengastia indica, A.leechi, Walchia micropelta and Microtrombicula munda.Conclusion(The chigger) mites species on R.flavipectus is very abundant with more individuals.The distribution of the chigger mites among different individuals of R.flavipectus is of an aggregation pattern.

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 generain 3 subfamilies of Trombiculidae . Theindividuals of eight dominant chigger mite species account for74 .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 canparasitize different species of small mammals hosts si multaneously ( more than five host species at least) and the highest onereaches 15 host species . The infestation rate and the mite index of dominant chigger mites on their corresponding hosts varyfrom2 .06 %to 59 .02 %and from0 .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 highestSreaches 58 while the diversity index on 15host species is beyond 1 with the highest H′=2.583 4 .Conclusion The chigger mite parasitismon small mammals is verycommonin the surrounding area of Erhai Lakein Dai pf Yunnan.The species of chigger mites are very abundant inthe area andtheir community structure is complicated . Most chigger mite species have abundant small mammal hosts with low hostspecificity .