Behavioral interactions between a coexisting rodent Micaelamys namaquensis and macroscelid Elephantulus myurus

A number of mechanisms are known to influence coexistence in small mammal communities. However, the role ofbehavioral interactions in promoting species coexistence is under-represented in the literature. We studied the behavioral interactionsof two coexisting small mammals, the Namaqua rock mouse Micaelamys namaquensis (Rodentia) and the Rock sengi Elephantulusmyurus (Macroscelidae), which have high dietary and microhabitat overlap. Using wild-caught individuals, intra- andinterspecific dyadic encounters were staged in tanks on a neutral rocky outcrop. Interspecific dyads displayed significantly moreactive avoidance behavior. There was no support for the prediction that the larger, more specialist species, E. myurus, is behaviorallydominant over M. namaquensis. Intraspecific encounters of E. myurus showed significantly more passive avoidance andamicable behavior, whereas the behavior of M. namaquensis did not differ between intra- and inter-specific encounters, both ofwhich were characterized by low levels of aggression and amicability. Thus, due to the lack of aggression, direct competition appearsweak and instead mutual avoidance may reduce or minimize interspecific interactions, potentially promoting coexistence.

中国滇西家鼠鼠疫宿主及媒介群落结构差异的流行病学意义

目的探讨云南省德宏、保山两个相邻家鼠鼠疫疫源地小哺乳动物及黄胸鼠体表蚤类群落组成与物种多样性差异的鼠疫流行病学意义。方法用群落内的优势种构成比、多样性及聚类分析，对1982—1996年的调查资料进行分析。结果两地区捕获的27种75490只小哺乳动物可划分为3个群落：群落Ⅰ[瑞丽居民区黄胸鼠（54．41％）＋大臭鼢（33．37％）]；群落Ⅱ[陇川、盈江居民区黄胸鼠（62．99％）＋大臭嗣（23．25％）＋小家鼠（10．06％）]；群落Ⅲ[保山居民区黄胸鼠（48．07％）＋大臭嗣（19．56％）＋灰麝鼢（14．37％）]。两地区所捕获黄胸鼠体表蚤类11种61122只划分为3个群落：群落i[瑞丽居民区印鼠客蚤（83．51％）＋野韧棒蚤（13．86％）]；群落ii[陇川、盈江居民区印鼠客蚤（74．42％）＋缓慢细蚤（22．94％）]；群落iii[保山居民区缓慢细蚤（70．62％）＋印鼠客蚤（22．70％）]。德宏地区在10个年份内，从7种宿主和5种媒介动物中分离到鼠疫菌1471株；保山地区仅在1个年份，从1种宿主和2种媒介动物中分离到鼠疫菌36株。另外德宏地区黄胸鼠、印鼠客蚤的构成比均较高，分别为58．70％和78．97％；宿主、媒介群落的物种多样性指数都较低，分别为1．010和0．625。而保山地区则与之相反，黄胸鼠和印鼠客蚤的构成比都较低，分别为48．07％和22．70％；宿主、媒介群落的物种多样性指数较高，分别为1．471和0．829。致使蚤类群落i-iii的主要优势蚤种，由印鼠客蚤转为缓慢细蚤。结论保山地区宿主、媒介群落物种多样性指数高，而主要宿主、媒介的构成比低，是降低该地区鼠疫流行的重要原因。