Rochette R, Dill LM, Himmelman JH
Departement de biologie et GIROQ, Universite Laval
Anim Behav. 1997 Nov;54(5):1053-62. doi: 10.1006/anbe.1997.0488.
In the Mingan Islands, the whelk Buccinum undatum displays defensive manoeuvres to both contact and water-borne chemical cues from the predatory asteroid Leptasterias polarisIn spite of this, whelks occasionally aggregate in great numbers near L. polaris while it is ingesting a prey; they then attempt to steal food from their predator and also wait for leftovers. In this study, the response of whelks in different types of encounters with L. polaris was examined to test the hypothesis that whelks are sensitive to the magnitude of the threat their predator represents. In a field experiment, whelks consistently fled both non-feeding and feeding L. polaris (asteroids used were consuming small prey items that were unlikely to provide food for whelks). When current flow was stable, whelks fled more directly down current and more frequently displayed violent defensive behaviours, in response to non-feeding L. polariswhich presented a higher risk, than in response to feeding asteroids (lower risk; 47% versus 2%). Consequently, whelks tested with non-feeding asteroids more rapidly distanced themselves from the predators than did whelks tested with feeding asteroids. In a field survey, there were more active whelks in the vicinity of cruising (higher risk) than stationary (lower risk) L. polaris (53% versus 14%). Among those whelks that were active, defensive behaviour patterns such as shell rocking and leaping escape movements were frequently shown by whelks near cruising predators (69%), but never by whelks near stationary predators (0%). The discriminative capabilities apparent in these results are likely to be adaptive, because they enable whelks to limit the cost of escape responses while still keeping predation risk low, and also because they facilitate a close association with L. polaris from which the whelks receive feeding benefits.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour
在明根群岛，蛾螺（Buccinum undatum）会对来自捕食性海星极地小海星（Leptasterias polaris）的接触和水体化学信号做出防御动作。尽管如此，当极地小海星正在捕食猎物时，蛾螺偶尔会大量聚集在其附近；然后它们试图从捕食者那里偷取食物，也会等待吃剩的食物。在本研究中，研究了蛾螺在与极地小海星的不同类型接触中的反应，以检验蛾螺对其捕食者所代表威胁程度敏感这一假设。在一项野外实验中，蛾螺始终会逃离不进食和正在进食的极地小海星（所使用的海星正在捕食小型猎物，这些猎物不太可能为蛾螺提供食物）。当水流稳定时，与正在进食的海星（风险较低；47%对2%）相比，蛾螺对不进食的、代表更高风险的极地小海星，会更直接地顺流逃离，并且更频繁地表现出激烈的防御行为。因此，用不进食海星进行测试的蛾螺比用进食海星进行测试的蛾螺更快地与捕食者拉开距离。在一项野外调查中，在巡游（风险较高）的极地小海星附近比在静止（风险较低）的极地小海星附近有更多活跃的蛾螺（53%对14%）。在那些活跃的蛾螺中，靠近巡游捕食者的蛾螺经常表现出诸如壳晃动和跳跃式逃脱动作等防御行为模式（69%），而靠近静止捕食者的蛾螺则从未表现出这些行为（0%）。这些结果中明显的辨别能力可能具有适应性，因为它们使蛾螺能够在将捕食风险保持在低水平的同时，限制逃脱反应的成本，还因为它们促进了与极地小海星的密切关联，蛾螺能从极地小海星那里获得进食的好处。版权所有1997动物行为研究协会1997动物行为研究协会
