DO PARASITES MAKE PREY VULNERABLE TO PREDATION - RED GROUSE AND PARASITES
DO PARASITES MAKE PREY VULNERABLE TO PREDATION - RED GROUSE AND PARASITES
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DOI：
10.2307/5623
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发表时间：
1992-01-01
影响因子：
4.8
通讯作者：
NEWBORN, D
中科院分区：
文献类型：
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作者：
HUDSON, PJ;DOBSON, AP;NEWBORN, D
1. 对松鸡进行广泛的尸检调查显示，春季和夏季被捕食者杀死的鸟类所携带的盲肠线虫细毛圆线虫数量明显多于秋季被射杀的松鸡。此外，似乎因寄生虫的影响而死亡的松鸡比被捕食者杀死的松鸡携带更多的蠕虫负担。2。通过饲养员密度间接测量，随着捕食者控制强度的增加，寄生虫感染水平较高的松鸡比例也随之增加。这两个经验观察表明，捕食者选择性地捕食严重感染的松鸡。3．通过用口服驱虫药减少雌性松鸡的蠕虫负担，对寄生虫和捕食者之间的相互作用进行了实验检查。随后，研究人员通过冲洗正在孵化的雌性鸟类，或通过训练过的通过气味定位鸟类的狗来定位经过处理和未经处理的雌性鸟类的巢穴。这些狗发现，接受治疗的鸟类明显少于对照鸟类，这表明携带大量寄生虫的雌性松鸡会散发出更多气味，并且更容易受到哺乳动物的捕食。4。描述了松鸡线虫系统的修改数学模型，该模型结合了对严重寄生松鸡的随机和选择性捕食的影响。该模型的分析说明了松鸡、寄生虫和捕食者之间相互作用在确定各自相对密度方面的重要性。特别是，当捕食者选择性地清除严重寄生的个体时，低水平的捕食可能会导致宿主（或猎物）种群规模的增加。
1. An extensive post-mortem survey of grouse revealed that birds killed by predators in spring and summer had significantly greater burdens of the caecal nematode Trichostrongylus tenuis than grouse shot during the autumn. Furthermore, grouse that appeared to have died through the effects of parasites carried greater worm burdens than grouse killed by predators.2. The proportion of grouse with high levels of parasite infection increased with the intensity of predator control as measured indirectly through keeper density. These two empirical observations suggest that predators selectively prey on heavily infected grouse.3. The interactions between parasites and predators were examined experimentally by reducing the worm burdens of female grouse with an oral anthelmintic. Nests of treated and untreated females were subsequently located either by research workers flushing the incubating female or by dogs trained to locate birds by scent. The dogs found significantly fewer of the treated than control birds, suggesting that female grouse with large parasite burdens emit more scent and are more vulnerable to mammalian predation.4. A modified mathematical model of the grouse-nematode system is described which incorporates the effects of both random and selective predation of heavily parasitized grouse. An analysis of the model illustrates the importance of interactions between grouse, parasites and predators in determining the relative densities of each. In particular, when predators selectively remove heavily parasitized individuals, then low levels of predation can lead to increases in the size of the host (or prey) population.