关键词: 体表寄生蚤, 物种多样性, 小型兽类, 群落结构, 分布格局

Abstract: Objective To investigate the composition and distribution of parasitic fleas of small mammals in Luquan Yi and Miao Autonomous County, Yunnan Province, China, identify the community structure and distribution of fleas, so as to provide basic data for exploring whether there are plague, endemic typhus, and other flea-borne diseases in Luquan County. Methods In Luquan County, an altitude range of 1 000 to 3 700 meters was divided into 6 vertical gradient zones at intervals of 500 meters. Three different habitats in residential areas, farming areas, and forest areas at varying altitudes were selected for the sampling of parasitic fleas of small mammals. Species were identified through morphological classification. The data were statistically analyzed using community ecology methods. Excel 2010 and SPSS 21.0 softwares were used for data collection and analysis, and rates were compared using the Chi-square test. Results A total of 259 parasitic fleas were captured from 408 small mammals, belonging to 19 species, 15 genera, and 6 families. The average flea infestation rate was 25.49%, with significant differences between the different small mammal species groups (χ²=52.116, P<0.01). The flea index of small mammals was 0.63. The dominant species were Ctenophthalmus quadratus and Neopsylla specialis specialis. The distribution of dominant flea species varied across different habitats and altitudes. Among the three habitats, the flea infestation rate and flea index of small mammals in residential areas were the highest. The flea infestation rate of small mammals in forest areas ranked second, with the flea index ranking third. The rate of flea infestation in farming areas was the lowest, with the flea index ranking second. There was no significant difference in the flea infestation rate on the body surface of small mammals in different habitats (χ²= 3.052, P=0.217). In different altitude zones, the flea infestation rates on the body surface of small mammals ranged from 7.69% to 44.44%, with significant differences observed between the different altitude zones (χ²=22.914, P<0.001) and a flea index ranging from 0.09 to 1.24. The species richness and quantity distribution of parasitic fleas on the body surface of small mammals increased gradually with the increase in altitude. The diversity index ranged from 0.544 to 1.712, gradually increasing and then decreasing with the increase in altitude within zones Ⅰ to Ⅲ; the index decreased to the lowest level within altitude zone Ⅳ, increased to the highest level in altitude zone Ⅴ, and gradually decreased in altitude zone Ⅵ. The trends in evenness and diversity were consistent, while the trend in the dominance was opposite, exhibiting a distribution pattern changing with the habitat heterogeneity at different altitudes. The diversity index of the three habitats ranged from 0.681 to 1.591, with the highest in farming areas, followed by forest areas, and then residential areas. The trends in richness and diversity index were consistent, and other indices varied by altitudes. Conclusions In Luquan County, the species richness and diversity of parasitic fleas on the body surface of small mammals are relatively high. Two major vectors of both domestic rodent and wild rodent plagues in Yunnan, Xenopsylla cheopis and N. specialis specialis, and various other natural zoonotic vector fleas exist, which provide vector conditions for the existence and epidemic transmission of plague and other epidemic diseases in natural foci. Therefore, the surveillance, prevention, and control of rodent-borne diseases such as plague should be strengthened.

Key words: Parasitic flea, Species diversity, Small mammal, Community structure, Distribution pattern