[Investigation of chigger mites on small mammals in a flatland area of Menghan, Xishuangbanna, Yunnan Province].

Objective To investigate the species composition and distribution of chigger mites on small mammals in flatland area in Menghan,Xishuangbanna of Yunnan Province. Methods The field investigation was made in a flatland area near Lancangjiang River in Menghan,Xishuangbanna of Yunnan Province. Small mammals were captured with mouse cages and traps. All mites on the hosts were collected and preserved in 70% ethanol. Hoyer′s solution was used to mount the chiggers on glass slides. The specimens of the chigger mites on the slides were finally identified into species under microscope. The constituent ratio,infestation rate,mean abundance and mean intensity of chigger mites in different habitats or on different hosts were used to measure the community structure. The species richness and community diversity were analyzed. Results A total of 233 small mammal hosts were captured(belonging to 2 families,3 genera and 5species). 5 763 individuals of chigger mites were identified as 2 subfamilies,7 genera,and 45 species. Rattus tanezumi(R. flavipectus) was the dominant species among the captured hosts,accounting for 97.4%(227/233). The mite infestation rate,average ectoparasite abundance,and mean mite intensity on R. tanezumi was 56.4%(128/227),24.7(5 600/227)and 43.8(5 600/128),respectively. Leptotrombidium deliense was dominant chigger mite species and account for 57.9%(3 337/5 763),mainly infested R. tanezumi. Compared with indoor and cultivated field habitats,the species richness and community diversity of chigger mites in shrub habitat were higher,and 41 species of chigger mites were collected.Conclusion The species composition and community structure is relatively simple in the flatland area in Xishuangbanna.L. deliense is the most dominant species of chigger mites and its main host is R. tanezumi.