Avian predators change their foraging strategy on defended prey when undefended prey are hard to find
Avian predators change their foraging strategy on defended prey when undefended prey are hard to find
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DOI：
10.1016/j.anbehav.2014.04.030
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发表时间：
2014-07-01
期刊：
影响因子：
2.5
通讯作者：
Rowe, Candy
中科院分区：
文献类型：
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作者：
Carle, Thomas;Rowe, Candy
视觉捕食者捕食具有一系列不同防御策略的猎物。最常被研究的两种防御策略是伪装（美味的和无防御的猎物有颜色图案，以尽量减少被发现）和警告（有毒的猎物用明显的警告信号来宣传它们的防御）。通常，这两种防御策略是单独研究的，但当多个猎物物种被相同的捕食者吃掉时，一个物种防御策略的变化可能会影响作用于另一个物种防御策略的选择压力。在这个实验中，我们通过调查当没有防御的猎物被更好地隐藏时，捕食者是否会增加对它们知道有毒的猎物的觅食行为来验证这一观点。欧洲椋鸟，Sturnus vulgaris，被允许在装有木屑的碗中自由觅食无防御（注入水）和防御（注入奎宁并涂覆）粉虫，黄粉虫（Tenebrio molitor）（猎物类型由碗的颜色表示）。有毒的猎物总是被30毫升的木屑覆盖，而没有防御的猎物则被30毫升或150毫升的木屑覆盖（所有的鸟都接受了两种木屑深度）。增加覆盖在不设防的猎物上的木屑的数量会使它们更难被发现，但不会影响鸟类寻找有毒猎物的倾向。然而，鸟类确实攻击并吃掉了更多的有毒猎物，但只有在它们接受150毫升的治疗之前，才会接受30毫升的治疗。我们的实验表明，更好地隐藏美味猎物可以增加对有毒猎物的捕食，这对猎物防御研究具有启示意义。(C) 2014动物行为研究协会。Elsevier Ltd.出版。版权所有。
Visually hunting predators forage on prey possessing a range of different defence strategies. The two most commonly studied defence strategies are camouflage (in which palatable and undefended prey have colour patterns to minimize detection) and aposematism (in which toxic prey advertise their defences using conspicuous warning signals). Typically, these two defence strategies are studied in isolation, but when multiple prey species are eaten by the same predators, changes in the defence strategy of one species could affect the selection pressures acting on the defensive strategy of another. In this experiment, we tested this idea by investigating whether predators increased their foraging behaviour on prey that they knew to be toxic when undefended prey were better concealed. European starlings, Sturnus vulgaris, were allowed to forage freely for undefended (water- injected) and defended (quinineinjected and coated) mealworms, Tenebrio molitor, in bowls containing woodchip (prey type was signalled by bowl colour). Toxic prey were always covered with 30 ml of woodchip, while undefended prey were covered with either 30 ml or 150 ml of woodchip (all birds received both woodchip depths). Increasing the amount of woodchip covering the undefended prey made them harder to find, but did not affect birds' propensity to search for toxic prey. However, birds did attack and eat more toxic prey, but only when they received the 150 ml treatment before the 30 ml treatment. Our experiment shows that better concealed palatable prey can increase predation of toxic prey, with implications for the study of prey defences. (C) 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.