| Objectives: This paper is an attempt to study the infestation, species composition, species diversity and the related issues of ectoparasites on the Yunnan red-backed vole(Eothenomys miletus), an endemic and specific species of rodent in China.Methods: The original data came from the field investigation in 27 counties of Yunnan Province from 2001 to 2012. Some conventional statistical methods were used to calculate the constituent ratio, prevalence, mean abundance and mean intensity of ectoparasites on E. miletus, which is to reflect the general infestation of the parasites. The dispersion coefficient, I index, Cassie’s Index and patchiness index were used to measure the spatial distribution of some dominant parasite species among different individuals of their vole host(E. miletus). Spearman’s correlation coefficient was used to analyze the linear correlation between the body parameters of the voles and their ectoparasite infestations. The methods of species abundance and species sample were used to analyze the relationships of species abundance distribution and species sample relation for the community of ectoparasites on E.miletus. The association coefficient was used to measure the interspecific relationship between different species of ectoparasites on the voles. The infestation and distribution of ectoparasites on the voles were compared among different altitude gradients.Results:(1) From 27 counties of Yunnan Province, 1,961 individual voles(E.miletus) were captured. From the body surface of 1,961 voles, a total of 56,063 ectoparasites were collected and these ectoparasites were then identified as comprising 206 species, 34 genera and 12 families. The overall prevalence(general infection rate) of the ectoparasites was 84.0%, and the overall mean abundance and mean intensity were 28.59 parasites/per examined vole and 34.02 parasites/perinfested vole. Of 56,063 ectoparasites collected and identified, there were 44,235 individuals of chigger mites, which were identified as 2 families, 12 genera and 130 species. There were 5,508 gamasid mites which were identified as 4 families, 11 genera and 53 species; 3,845 sucking lice were identified as 2 families, 2 genera and 9species; 2,475 fleas belonged to 4 families, 9 genera and 14 species.(2) Of 4categories of ectoparasites collected from the body surface of E. miletus, chigger mites had the highest species and individuals and gamasid mites came next. Of 130 species of chigger mites, Leptotrombidium scutellare was the most abundant species,which accounted for 22.6% of the total 130 species. Laelaps chini was the most dominant species of gamasid mites, which accounted for 70.0% of the total 53 species of gamasid mites. Of 9 species of sucking lice, the constituent ratio of Hoplopleura edentula was the highest(97.8%). Ctenophthalmus quadratus was the most abundant species of fleas, which accounted for 83.6% of the total 14 species of fleas.(3) The spatial distribution of 9 dominant species of ectoparasites, including Leptotrombidium scutellare, L. sinicum and Laelaps chini, showed an aggregated pattern among different individuals of their host, E. miletus.(4) There were some differences in the infestation of ectoparasites between female and male voles(E. miletus). Both the overall mean abundance and mean intensity of the parasites in male voles were higher than those in the females(P<0.05). The prevalence of the parasites between the male and female voles, however, showed no significant difference(P>0.05).(5) A linear correlation existed between the weight and length of E. miletus(r=0.753, P<0.001).The individuals of sucking lice showed a slightly positive correlation with the weight and length of their host, E. miletus(r=0.071, r=0.065, P<0.05). There were no linear correlation between species and individuals of chigger mites, gamasid mites, fleas and the weight and length of the host voles.(6) The tendency curve of species abundance of all the ectoparasite community showed that there were few dominant species with a large number of individuals in the community. Some rare species of ectoparasite only had one individual. The common species were the majority of the parasite species in the community and they took the peak of the tendency curve of the species abundance distribution. The species abundance distributions of a separate category of ectoparasites(chigger mites, gamasid mites, sucking lice and fleas) did not have the above tendency curve.(7) The tendency curve of species sample relation showed that the number of the parasite species went up rapidly with the increase of the hostsamples(the individuals of E. miletus) in the beginning. When the increase of the host samples reached a certain level, the tendency curve went up very slowly and was finally closed to a horizontal line.(8) The species sample relations of a separate category of ectoparasites(chigger mites, gamasid mites, sucking lice and fleas) did not have the above tendency curve. There was no prominent interspecific association between different species of ectoparasites with a very weak association coefficient,which were between 0.062 and 0.126(P<0.01).(9) The overall mean abundance of ectoparasites on E. miletus showed the highest value in the middle altitude gradients between 2,000 meters and 2,999 meters.Conclusions:(1) The Yunnan red-backed vole(Eothenomys miletus) have a great potential to harbor many species of ectoparasites. The number of the parasite species found on this single species of rodent even exceeds the species from multiple species of rodent hosts in some previous investigations. The infestation of ectoparasites on E. miletus is common with a high overall prevalence and mean abundance. Of the four categories of ectoparasites, chigger mites are the most abundant with more species and individuals. Gamasid mites come next. All the dominant species of ectoparasites showed an aggregated pattern of spatial distribution on their vole host, E. miletus. There is no prominent interspecific association between different parasite species. The overall mean abundance and mean intensity in male voles are higher than those in the females.(2) The body parameters(body weight and body length) of the vole hosts show no prominent influence on the infestation of ectoparasites.(3) The infestation of ectoparasites on E. miletus varies along the different altitude gradients, which is highest in the middle altitudes from 2,000 meters to 3,000 meters. |
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