Communities of gamasid mites on Eothenomys miletus in southwest China

The Yunnan red-backed vole ( Eothenomys miletus ) is an endemic and specific wild rodent species in China. From 39 sites across southwest China, a total of 12,536 individuals of gamasid mites were collected from 2,463 voles between 2001 and 2013. The 12,536 mites were identified as comprising 106 species, 26 genera and 9 families. The overall mite prevalence and mean abundance from all the voles were 48.36% and 5.09 mites/per examined vole, respectively. Laelaps chini ( C r = 81.24%) was the dominant mite species. The gamasid mite infestation of E. miletus is common with a very high species diversity (S = 106). The spatial distribution pattern of the dominant species ( L. chini ) was analyzed by using some indices, including the dispersion coefficient, aggregated indices, Cassie index, patchiness index, mean crowding and negative binomial distribution parameter. The established Iwao’s equation was M* = 5.516 + 2.312 M ( r = 0.942, P < 0.05) with higher α and β than 0 and 1 (the border values for determining spatial pattern), respectively, and the F value was 81.66 ( P < 0.05) in the significance test of random deviation ( F -test). The spatial distribution pattern of L. chini among the individuals of E. miletus was then determined as an aggregated distribution, which means that L. chini has a tendency to clump together and form different individual groups on the body surface of E. miletus. The distribution of species-abundance showed that with the increase of gamasid mite individuals, the number of the mite species gradually decreased, which indicates that most mite species are rare species. The curve tendency of species-sample relationship showed that the number of gamasid mite species increased with the increase of the host samples (number of individuals of E. miletus). The results suggest that a large host sample is recommended in the future field investigations for the species composition and species diversity of gamasid mites on rodents.