A direct comparison of the effectiveness of two anti-predator strategies under field conditions
A direct comparison of the effectiveness of two anti-predator strategies under field conditions
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DOI：
10.1111/jzo.12074
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发表时间：
2013-12-01
影响因子：
2
通讯作者：
Sherratt, T. N.
中科院分区：
文献类型：
--
作者：
Carroll, J.;Sherratt, T. N.
警告和隐藏是生物进化出来的两种广泛的防御策略，以减少捕食者的攻击。然而，尽管两者都被广泛研究过，但对不好吃的显眼猎物的捕食率很少直接与对美味的隐蔽猎物的捕食率进行比较，而且从未在野外进行过。在本研究中，我们使用既定的方法来比较这两种防御特性的有效性，通过在自然野外环境中将人工猎物目标放置在受到野生鸟类捕食者攻击的树上。当被部分吃掉的猎物和被完全吃掉的猎物都被认为受到了捕食者的攻击时，采用两种防御策略的目标之间的攻击率没有差异。然而，示警猎物被完全吃掉的次数比隐蔽性猎物少，而部分被吃掉的次数更多。这表明捕食者会对不美味的猎物进行味觉排斥，或者更谨慎地捕食显眼的猎物（慢速捕食）。我们还观察到，在不同的实验地点之间，尽管它们的相似性和相对接近，但在捕食方面存在显著差异，这表明在野外，猎物可能会经历高度变化的捕食。如果发出警告的猎物能够在捕食者的攻击中幸存下来，那么这就代表了发出警告的潜在防御优势。
Aposematism and crypsis are two widespread defensive strategies that have evolved in organisms to reduce attacks by predators. However, although both have been studied extensively, predation rates on unpalatable conspicuous prey have seldom been directly compared to those on palatable cryptic prey, and never in the field. In this study, we use established methods to compare the effectiveness of both defensive traits, by presenting artificial prey targets on trees where they were subject to attack by wild avian predators in a natural field setting. When partially consumed prey and those that had been completely removed were both treated as attacked by predators, there were no differences in attack rates between targets with the two defensive strategies. However, aposematic prey were completely consumed less often than cryptic prey, and partially consumed more often. This suggests that predators engage in taste rejection of unpalatable prey and/or feed on conspicuous prey more cautiously (go-slow' predation). We also observed significant differences in predation among experimental sites, in spite of their similarity and relatively close proximity, and among trials, which suggests that prey may experience highly variable predation in the wild. If aposematic prey are capable of surviving attacks by predators, then this represents a potential defensive benefit of aposematism over crypsis.