[Study of chigger communities on major species of rodents in Yunnan Province]

To understand the characteristics of the chigger communities on the major species of rodent hosts.

Rats were captured in 16 counties (or towns) of Yunnan. All the mites on the two auricles of the host were collected and identified. Shannon-Weiner's indices (H,E), the richness indices and dominance indices were adopted to judge the diversity and community structure of chiggers on their hosts (7 species of rodents).

From the 7 species of dominant rodent hosts, 131 species of chiggers were identified, belonging to 17 genera of Trombiculidae. Among them, abundant individuals were collected from 6 species which were considered to be dominant chigger species. Shannon-Weiner's indices (H) of the chigger communities showed the following sequence: Rattus norvegicus>Apodemus chevrieri>Eothenomys miletus>Mus pahari>Rattus nitidus>Rattus flavipectus>Mus caroli, and the richness indices were similar to this tendency. The niche breadth of the 6 dominant chigger species showed the following tendency: Herpetacarus hastoclavus>Leptotrombidium scutellare>Leptotrombidium sinicum>Helenicula siena>Leptotrombidium hiemalis>Leptotrombidium eothenomydis. There was a wide niche overlap between any two chigger species with all indices beyond 0.76. Slight positive association existed between each two dominant species of chigger mites by the coefficient of association (V).

The community structure of chigger mites on the 7 major species of rodent hosts is complex, reflecting a high diversity of mite species. The niche breadth of the 6 dominant chigger species is different with a wide niche overlap.