Boyard C, Barnouin J, Gasqui P, Vourc'h G
INRA (Institut National de la Recherche Agronomique), UR346 Epidémiologie Animale, F-63122 Saint Genès Champanelle, France.
Parasitology. 2007 Jul;134(Pt 7):987-94. doi: 10.1017/S0031182007002351. Epub 2007 Feb 12.
Although Ixodes ricinus ticks are mainly associated with woodland, they are also present in open habitat such as pastures. The distribution of nymphal I. ricinus was monitored by drag sampling the vegetation in May-June 2003 on 61 grazed permanent pastures for cattle located in central France. After selecting explanatory variables from among a set of 155, tick abundance was modelled on the perimeter of the pasture using a negative binomial model that took into account data overdispersion. An abundant tree layer at the perimeter of the pasture associated with a high humidity before sampling greatly enhanced the average number of captured I. ricinus nymphs. The presence of apple or cherry trees around the pasture perimeter, the presence of trees or bushes at the pasture edge, woodland around the pasture and a high number of I. ricinus nymphs in the nearest woodland to the pasture were also favourable to nymph abundance in the pasture. The study highlighted that woodland vegetation associated with humidity and the presence of attractive foraging areas for tick hosts around the pasture played a key role in the abundance of I. ricinus. Finally, the results raised the question of whether and how transfer of ticks between woodland and grazed pastures occurs.
虽然蓖麻硬蜱主要与林地有关，但它们也存在于开阔栖息地，如牧场。2003年5月至6月，通过在法国中部61个用于放牧牛的永久性牧场上对植被进行拖拽采样，监测了蓖麻硬蜱若虫的分布。从155个变量中选择解释变量后，使用考虑了数据过度离散的负二项式模型，以牧场周边为基础对蜱虫丰度进行建模。采样前牧场周边丰富的树木层以及高湿度极大地增加了捕获的蓖麻硬蜱若虫的平均数量。牧场周边有苹果树或樱桃树、牧场边缘有树木或灌木丛、牧场周围有林地以及牧场最近林地中有大量蓖麻硬蜱若虫，也有利于牧场中若虫的丰度。该研究强调，与湿度相关的林地植被以及牧场周围存在对蜱虫宿主有吸引力的觅食区域，对蓖麻硬蜱的丰度起着关键作用。最后，研究结果提出了蜱虫在林地和放牧牧场之间是否以及如何转移的问题。
