Lindsay L R, Mathison S W, Barker I K, McEwen S A, Surgeoner G A
Department of Pathobiology, University of Guelph, ON, Canada.
J Med Entomol. 1999 May;36(3):243-54. doi: 10.1093/jmedent/36.3.243.
Ixodes scapularis Say populations were evaluated within 4 habitats on Long Point, Ontario, from 1990 to 1992 to ascertain whether differences in density of mouse populations within and among habitats were correlated with that of immature I. scapularis populations. I. scapularis immatures were rarely collected by dragging within the cottonwood dune habitat. Significantly more larvae (P < or = 0.05) were collected by drag sampling within the maple forest habitat than in the oak savannah or white pine habitats for the 1989, 1990, and 1991 cohorts, whereas the size of the 1992 larval cohort did not differ significantly among these habitats. Significantly more nymphs were collected by dragging within the maple forest than in the other 2 habitats for all 4 cohorts. Nymphs from the 1989 and 1990 cohort were more abundant within the oak savannah than the white pine habitat, whereas the 1991 and 1992 cohorts were similar. With few exceptions, I. scapularis immatures were most prevalent on white-footed mice, Peromyscus leucopus (Rafinesque), captured within the maple forest > oak savannah > white pine > cottonwood dune, although differences were not significant in all years and in all habitats. The number of mice captured within the 4 habitats was not correlated with the number of I. scapularis larvae or nymphs infesting them. Likewise, the minimum number of mice alive was not significantly correlated with conversion indices of larvae to nymphs or nymphs to adults. Lack of association between mouse availability and relative size of subsequent cohorts of host-seeking ticks suggests that factors other than the size of the mouse populations were responsible for the observed differences in tick abundance among habitats.
1990年至1992年期间，对安大略省长角的4个栖息地内的肩突硬蜱种群进行了评估，以确定栖息地内和栖息地间小鼠种群密度的差异是否与未成熟肩突硬蜱种群的密度差异相关。在三角叶杨沙丘栖息地内，通过拖网很少能采集到未成熟的肩突硬蜱。对于1989年、1990年和1991年的幼虫群体，通过拖网采样在枫树林栖息地采集到的幼虫显著更多（P≤0.05），高于橡树稀树草原或白松林栖息地，而1992年幼虫群体的数量在这些栖息地之间没有显著差异。对于所有4个群体，通过拖网在枫树林内采集到的若虫显著多于其他2个栖息地。1989年和1990年群体的若虫在橡树稀树草原比在白松林栖息地更为丰富，而1991年和1992年群体的情况相似。除了少数例外情况，未成熟的肩突硬蜱在白足鼠（白足鼠属，拉芬斯克）上最为常见，在枫树林中捕获的白足鼠>橡树稀树草原>白松林>三角叶杨沙丘，尽管在所有年份和所有栖息地差异并不显著。在4个栖息地内捕获的小鼠数量与感染它们的肩突硬蜱幼虫或若虫数量没有相关性。同样，存活小鼠的最小数量与幼虫到若虫或若虫到成虫的转化指数也没有显著相关性。小鼠可获得性与随后寻找宿主的蜱虫群体相对大小之间缺乏关联，这表明除小鼠种群大小之外的因素导致了不同栖息地间观察到的蜱虫丰度差异。
