云南省大理洱海周边地带小兽体表恙螨种群空间分布型研究

目的 研究云南省大理洱海周边地带小兽宿主体表恙螨种群空间分布类型。方法 应用扩散系数（C）、丛生指数（I）、Cassie指数（CA）及聚块指数（m^＊／m）进行分析。结果 捕获小兽3313只，经鉴定隶属7科14属21种。从3313只小兽双侧耳壳、耳窝共采获恙螨56150只，经鉴定隶属3亚科13属109种。在分类统计的基础上选定8种恙螨为种群空间分布型测定对象，6种小兽为宿主样方单位。4种分布型指数的测定结果表明，8种优势恙螨在其对应宿主体表的空间分布均表现为聚集分布，各数值明显大于界限值0或1。结论 云南省大理洱海周边地带小兽宿主体表恙螨种群空间分布类型既不是随机的，也不是均匀的，而呈聚集型分布，恙螨在小兽体表呈群居寄生。

Studies on Spatial Pattern of Chigger Mite Populations on Small Mammals in the Surrounding Areas of Erhai Lake in Dali of Yunnan

Objective To study the spatial pattern of the chigger mite populations on the body surface of small mammals in the surrounding areas of Erhai Lake in Dali of Yunnan, China. Methods Coefficient(C), clumping index(I), Cassie index(C_A) and patch index( m~/m ) were used to analyze the spatial patterns of chigger mite populations. Results The captured 3 313 small mammals were identified as 21 species and 14 genera in 7 families. 56 150 individuals of chigger mites were collected from the two auricles of 3 313 small mammal hosts and they were identified as 109 species and 13 genera in 3 subfamilies of Trombiculidae. Eight main species of chigger mites were selected as target and the spatial pattern of eight main species of chigger mites (populations) were measured among different individuals of six species of small mammals. The results reveal that all the numeric values from four kinds of indices (C, I, C_A and m~/m) are much higher than their border values (0 or 1) and the spatial distribution patterns of eight main chigger mite populations are therefore determined as the aggregated patterns of distribution among the different individuals of their hosts, small mammals. Conclusion The studied chigger mites from the surrounding area of Erhai Lake in Dali of Yunnan neither evenly nor randomly distribute among the different individuals of their small mammal hosts, but aggregately gather on the body surface of some hosts, forming aggregated ectoparasitic groups of the mites on small mammal hosts.