Infestation and Related Ecology of Chigger Mites on the Asian House Rat (Rattus tanezumi) in Yunnan Province, Southwest China

Abstract

This paper is to illustrate the infestation and related ecological characteristics of chigger mites on the Asian house rat (Rattus tanezumi). A total of 17,221 chigger mites were collected from 2,761 R. tanezumi rats, and then identified as 131 species and 19 genera in 2 families. Leptotrombidium deliense, the most powerful vector of scrub typhus in China, was the first major dominant species on R. tanezumi. All the dominant mite species were of an aggregated distribution among different individuals of R. tanezumi. The species composition and infestations of chiggers on R. tanezumi varied along different geographical regions, habitats and altitudes. The species-abundance distribution of the chigger mite community was successfully fitted and the theoretical curve equation was. Ŝ (R)=37e–(0.28R)2 The total chigger species on R. tanezumi were estimated to be 199 species or 234 species, and this further suggested that R. tanezumi has a great potential to harbor abundant species of chigger mites. The results of the species-plot relationship indicated that the chigger mite community on R. tanezumi in Yunnan was an uneven community with very high heterogeneity. Wide geographical regions with large host samples are recommended in the investigations of chigger mites.

Infestation of chigger mites on Chinese mole shrew,Anourosorex squamipes, in Southwest China and ecological analysis

“…A previous study showed that a total of 61 chigger species were identified from the brown rat (Norway rat, Rattus norvegicus ) in Yunnan Province, Southwest China and the infestation indices of chiggers on R. norvegicus ( P m = 13.4%, MA = 1.27 and MI = 9.49) are close to those on A. squamipes ( P m = 11.1%, MA = 1.87 and MI = 16.86) in the present study [ 5 ]. In contrast, a total of 131 species of chigger mites were previously identified from the oriental house rat (Asian house rat, R. tanezumi ) in Yunnan, with higher infestation indices ( P m = 20.9%, MA = 6.20 and MI = 29.80) [ 6 ], and 175 chigger species were identified from the large Chinese vole (large oriental vole or Yunnan red-backed vole, E. miletus ) in Southwest China, with much higher infestation ( MA = 20.24, 49850/2463) [ 43 ]. The species diversity ( S = 71) and infestation of chiggers on A. squamipes are obviously lower than those on R. tanezumi and E. miletus [ 6 , 43 ].…”

“…In contrast, a total of 131 species of chigger mites were previously identified from the oriental house rat (Asian house rat, R. tanezumi ) in Yunnan, with higher infestation indices ( P m = 20.9%, MA = 6.20 and MI = 29.80) [ 6 ], and 175 chigger species were identified from the large Chinese vole (large oriental vole or Yunnan red-backed vole, E. miletus ) in Southwest China, with much higher infestation ( MA = 20.24, 49850/2463) [ 43 ]. The species diversity ( S = 71) and infestation of chiggers on A. squamipes are obviously lower than those on R. tanezumi and E. miletus [ 6 , 43 ]. The results indicate that different species of small mammals (rodents and shrews) have different potential to harbor chiggers with different species diversity and infestation of the mites, which is associated with the different biological characteristics of different host species [ 5 , 6 , 40 ].…”

“…The species diversity ( S = 71) and infestation of chiggers on A. squamipes are obviously lower than those on R. tanezumi and E. miletus [ 6 , 43 ]. The results indicate that different species of small mammals (rodents and shrews) have different potential to harbor chiggers with different species diversity and infestation of the mites, which is associated with the different biological characteristics of different host species [ 5 , 6 , 40 ].…”

“…The species similarities of chigger were low in different latitudes, altitudes, habitats, and landscapes ( J < 0.5). The results indicate that the infestation of chiggers on the same host species ( A. squamipes ) was not stable and fluctuates in different environments, which may be related to the environmental heterogeneity and the low host specificity of chiggers [ 6 , 40 , 69 ]. Different chigger species usually have different adaptability to different environmental conditions [ 30 , 35 , 68 ].…”

“…in different latitudes, altitudes, habitats, and landscapes, and this may be suitable to the growth, development, and reproduction of different chigger species [ 63 , 65 ]. For example, there are usually far more species of plants and animals with much higher biodiversity and vegetation in outdoor habitats such as bushes, woodlands, and farmlands than in indoor and residential habitats such as houses, stables, barns, and nearby surroundings [ 6 , 40 , 62 ], and this may explain why the species richness and infestation indices of chiggers on A. squamipes in the habitats of bushes, woodlands and farmlands are higher than those in the residential areas ( Table 4 ). The infestation fluctuation of chiggers in different environments also reflects the influence of environmental factors on chiggers [ 30 , 35 , 63 ].…”