PARASITE AVOIDANCE - THE CAUSE OF POST-CALVING MIGRATIONS IN RANGIFER
PARASITE AVOIDANCE - THE CAUSE OF POST-CALVING MIGRATIONS IN RANGIFER
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DOI：
10.1139/z91-340
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发表时间：
1991-09-01
影响因子：
1.4
通讯作者：
ANDERSEN, J
中科院分区：
文献类型：
--
作者：
FOLSTAD, I;NILSSEN, AC;ANDERSEN, J
对屠宰的驯鹿(Rangifer tarandus tarandus L.)来自挪威北部芬马克县不同的夏季牧区。为了检验这一假设，即幼虫丰度随着产后迁徙距离(即离产犊地的距离)的增加而减少，对不同迁徙距离的牛群进行了抽样。在1168只动物样本中，感染率为99.9%。研究表明，来自不同夏季放牧区的牛群幼虫丰度存在显著差异。与整个夏天留在产卵场或附近的牛群相比，产后迁徙的牛群的幼虫丰度明显较低。塔兰迪幼虫丰度的群体间差异被认为反映了群体夏季范围内感染阶段(成虫)密度的不同。幼虫在群体中的丰度反过来又与主要幼虫脱落区(即产奶场)和最大传播区(即夏季牧场)之间的距离呈负相关。这些结果与Rangifer常见的其他寄生虫的传播有关，并表明这种宿主在产犊后的迁徙可能是一种行为适应，降低了寄生虫感染水平。
Intensities of warble fly larvae, Hypoderma tarandi (L.), were examined in slaughtered reindeer (Rangifer tarandus tarandus L.) from different summer grazing areas of Finnmark County, northern Norway. To test the hypothesis-that larval abundance decreases with increase in post-calving migration distance (i.e., distance from calving grounds), herds with differing migration distances were sampled. The prevalence of infection in the total sample of 1168 animals was 99.9%. The study revealed significant differences in larval abundance among herds from different summer grazing areas. Herds with post-calving migrations have significantly lower larval abundances than herds remaining on or near the calving grounds for the whole summer. Between-herds variation in abundance of H. tarandi larvae is assumed to reflect differing densities of the infective stage (adult flies) on the herds' summer ranges. Larval abundance in a herd is in turn negatively correlated with the distance between the main larval shedding areas (i.e., calving grounds) and the areas of greatest transmission (i.e., summer pastures). These results are discussed in relation to transmission of other parasites common to Rangifer and suggest that this host's post-calving migration may be a behavioural adaptation that reduces levels of parasitic infections.