Objective To determine the niche breadth and overlap in eleven dominant species of gamasid mites parasitic on 39 species of small?mammal hosts around Biluoxueshan Mountain in Weixi, Yunnan. Methods The niche breadth was determine using the Levins model, the niche overlap the Colwell?Futuyma model, based on which the systematic grouping of niche overlap for all gamasid mites was completed by cluster analysis. Results （1） Eulaelaps huzhuensis and Hypoaspis pavlovskii had the widest niche breadth (0.1067 and 0.1044), while Laclaps traubi Domrow and Haemogamasus sanxiaensis had the narrowest (0.0390  and  0.0365). （2）L. traubi  Domrow  and  L. turkestanicus  shared  a  highly  similar  population  distribution  with  L. chin, Ha. oliviformis and Hy. pavlovskii. Conclusion The niche breadth could be used as an index for evaluating the host specificity of gamasid mites, whose similarity in population distribution was largely related to that of their hosts, as well as their taxonomic distance.

【Abstract】 Objective To investigate the geographical distribution, habitat, dominant hosts and population spatial distribution patterns of Ornithonyssus bacoti in Yunnan province.  Methods   A total of 28 counties in five zoogeographical sub?regions were chosen as the investigated sites. Each investigated site was divided into two habitats (indoors and outdoors) and then small mammal hosts were randomly captured by mouse traps. All the gamasid mites from the body surface of the hosts were collected and preserved in 70% ethanol. Hoyer’s medium was used to mount the mites onto glass slides and each mite specimen was finally identified by microscope. The spatial pattern of the mite was analyzed by K?value of negative binomial distribution, patchiness index, Taylor’s power function and Iwao’s model.  Results A total of 3339 O. bacoti were collected from 11 560 captured  small  mammal  hosts  which belonged to 3 orders 4 families 8 genera  and  15  species.  Of  the  investigated 28 counties, O. bacoti was found in 21 counties and the mites were collected from 15 species of small mammal hosts. O.bacoti mainly distributed in Southwest region (accounted for 90% of the total), and the quantity of O. bacoti in indoors (2914, 87.27%) were obviously higher than that in outdoors (425, 12.73%).  90% mites mainly parasitized on the body surface of Rattus norvegicus and R. tanezumi which were  the  dominant  host  of  mites.  The  results  showed  that  the  spatial  pattern  of  O. bacoti  was  an  aggregated  distribution. Conclusion O. bacoti  widely  distributes  in  Yunnan  province  and  mainly  parasitizes  on  the  body surface of R. norvegicus and R. tanezumi. It is of aggregated distribution among its main hosts.

【Abstract】 Objective To illustrate the similarity， transitional tendency and classification of gamasid mite communities in the surrounding areas of Biluoxueshan in Weixi county of Yunnan province. Methods System clustering analysis was used in this study. Results In 1560 small mammals captured， the dominant species of mites from Apodemus draco， Eothenomys miletus， Niviventer confucianus， Ap.chevrieri, Ap.peninsulae, Rattus norvegicus and R.tanezumi were Laelaps jingdongensis（Dr＝41.32）, L.chin（Dr＝41.87）,  L.traubi （Dr＝63.51） and L.turkestanicus （Dr＝24.78）, L.traubi（Dr＝18.82）,  Eulaelaps huzhuensis（Dr＝14.11） and L.chin（Dr＝11.76）, E.huzhuensis（Dr＝25.00）, E.huzhuensis（Dr＝23.61） and Haemogamasus oliviformis（Dr＝16.67）, Ornithonyssus bacoti（Dr＝71.73） and O.bacoti（Dr＝98.82）, respectively. The result of system clustering analysis indicated that there was prominent similarity between the gamasid mite from R.norvegicus and R.tanezumi, secondly it was the similarity among the mites from Ap.draco, Ap.peninsulae and Ap.chevrieri. Conclusion  The taxonomic relations of mite hosts was nearer, the communities similarity of gamasid mite was higher. The habits distribution of hosts had an effect on communities type of parasitic gamasid mite.

【Abstract】 Objective To study the distribution and its ecological charateristics of medical gamasid mites in the surrounding areas of Biluoxueshan in Yunnan province, China. Methods Some small mammals were captured by mouse traps (or mouse clips) in the surrounding areas of Biluo snow mountain located in Weixi county of Yunnan province. The ectoparasitic gamasid mites were all collected from the body surface of small mammal hosts. The community structure of gamasid mites were illustrated with richness （S）, Shannon?Wiener’s diversity index（H′）, evenness（J′） and dominance index（C′）. The spatial distribution patterns of some dominant species of gamasid mites were measured by disperse coefficient, clumping index, Cassie index and patch index. Results There were 1560 small mammals belonging to 40 species captured, and 35 species of gamasid mites were collected from the body of small mammals. Of which, 8 species were not identified. The community of gamasid mites showed a high diversity with abundant species. The dominant species of gamasid mite were Laclaps traubi, Laelaps chin, Laelaps jingdongensis, Laclaps turkestanicus and Ornithonyssus bacoti. The distribution patterns of 5 dominant gamasid mite species on the body of small mammals were of aggregated distribution. Of the 5 dominant species, the female ratios of most mite species （96.84%, 87.94%, 92.78%, 95.77%） were much higher than the males, but Os.bacoti was an exception （37.25%）. For most mites species, the proportion of the larvae and nympha was much lower with the exception of Os.bacoti Hirst （54.51%）. Conclusion The community of gamasid mites in the surrounding areas of Biluo snow mountain was relatively complicated with abundant species. The spatial distribution of dominant mite species was of aggregated distribution pattern.