Objective To investigate the ecological niches of sucking lice (Phthiraptera: Anoplura) on the body surface of small mammal hosts and the co-evolutionary relationship between lice and mammal hosts in Yunnan Province. Method Thirty species of small mammals were captured and used as 30 resource sequences. The distribution and composition of the dominant 22 species of sucking lice on the body surface of the 30 species small mammal hosts were analyzed as the utilization proportion for each resource sequence. The niche breadth and proportional similarity were measured. SPSS 13.0 statistical software was used for analyzing the niche overlap matrix of sucking lice by hierarchical clustering analysis, and a dendrogram was made. Results The niche breadth was narrow for most species of sucking louse. Among the detected species, Hoplopleura pacifica showed the widest niche breadth, but only 0.1536. Indices of niche proportional similarity of most sucking lice were relatively small from 0.0005 to 0.4695. The 22 species of sucking lice were classified into 16 niche overlap groups, by ?=5.5, through a hierarchical clustering analysis for the niche overlaps, and the clustering process of most sucking lice was late. Conclusion The sucking lice have a high specificity for hosts, of which different species show an apparent niche divergence on host selection. The results reveal a high coevolution between sucking lice and the mammal hosts.

Objective To understand the species diversity of ectoparasites on Niviventer confucianus in the surrounding areas of Erhai Lake.Methods Small mammals were randomly captured in 12 investigated sites surrounding Erhai Lake with baited mouse cages.The cage-traps were examined and re-baited each morning.Trapped small mammals were brought to the laboratory for identification according to color, body length, ear length, hind foot length.All ec-toparasites on the surface of the hosts were collected and identified.The constituent ratio(C), prevalence(P) and average ectoparasite abundance(A) were used to evaluate the prevalence and density of ectoparasites.Non-parametric Mann-Whitney U-test was used to test differences in the abundance and richness of ectoparasites between female and male hosts.Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body param-eters of hosts.Results Eighty-nine individuals of N.confucianus were captured, of which 79% were found infested with 51 species of ectoparasites, including 31 species of chigger mites, 13 species of mesostigmatid(gamasid) mites, 4 species of fleas and 3 species of sucking lice.Walchia ewingi Fuller(66.2%), Laelaps turkestanicus Lange(38.5%), Paradoxopsyllus custodies Jordan(42.9% ) and Hoplopleura pacifica(80.1% ) were the most predominant species of chigger mites, gamasid mites, fleas, and sucking lice, respectively.Non-parametric Mann-Whitney U-test showed that there was no significant difference between male and female hosts on the species richness and abundance of total ec-toparasites, chigger mites, sucking lice, fleas or gamasid mites.Spearman correlation analysis showed that the abun-dance and species of total ectoparasites, chigger mites, sucking lice, fleas or gamasid mites were not correlated with the body weight of hosts.Conclusion There is a high speices diversity of ectoparasites on N.confucianus.Sucking lice, fleas, chiggers and gamasid mites are the main ectoparasites.

Objective To understand the species,species distribution,the dominant species and their interspecies interaction of chigger mites on Eothenomys miletus(a dominant species of rats)in Yunnan.Method The rats were captured with mouse traps in 16 counties(or cities)during 2000-2004.All mites on the surface of two auricles of the hosts were collected and identified.The patch index(m*/m)and the coefficient of association(V)were adopted to judge the spatial distribution patterns and interspecies interaction of the dominant chigger mite species among different individuals of the rats(E.miletus).Results 1157 individuals of E.miletus were captured from 16 counties(citys).37613 chigger mites(belonging to 3 subfamily,9 genus and 80 species)were collected from the auricles(body surface)of 1157 rat hosts with a high “overall mite infestation rate”(68.2%)and “overall mite index”(32.5).Six species of mites were found dominant on E.miletus:Leptotrombidium scutellare,Leptotrombidium sinicum,Helenicula simena,Leptotrombidium eothenomydis,Herpetacarus hastoclavus and Leptotrombidium hiemalis.The distribution of the chigger mites among different individuals of E.miletus showed an aggregation pattern.Both positive and negative association existed between each two dominant species of chigger mites.Conclusion The species composition of chigger mites on Eothenomys miletus is complex with abundant individuals,which reflects a high species diversity of the mites.The main species of chigger mites tend to an aggregation on the body surface of E.miletus.

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).Conclusion 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.