Colour change and assortment in the western rainbowfish
Colour change and assortment in the western rainbowfish
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DOI：
10.1016/j.anbehav.2010.01.017
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发表时间：
2010-05
期刊：
影响因子：
2.5
通讯作者：
Gwendolen M. Rodgers;J. Kelley;L. Morrell
中科院分区：
文献类型：
--
作者：
Gwendolen M. Rodgers;J. Kelley;L. Morrell
这种行为在动物王国中很普遍，并且被认为可以减少个体被捕食的风险，例如通过捕食者混淆。理论预测，与群体中其他人外表不同的个体被捕食的风险更大，因为他们对捕食者来说更显眼（“古怪”效应）。因此，动物应该选择与自己外表最相似的群体伴侣。另一种常见的反掠食者战术是伪装。鱼类能够改变颜色以匹配其视觉背景，但很少有研究探讨这可能如何影响浅滩决策，特别是在奇怪效应的背景下。我们诱导颜色图案的变化，在一个色彩缤纷的淡水鱼，西部彩虹鱼，Melanotaenia australis，保持鱼在黑暗和苍白的水族馆2周。对黑色身体色素沉着比例的分析证实，在黑暗环境中的彩虹鱼比在苍白环境中的彩虹鱼形成了更深的颜色图案。然后，我们进行了行为观察，以确定鱼是否随后根据他们的浅滩决定身体着色。我们发现，彩虹鱼喜欢浅滩与类似的个人，鱼一直在黑暗的水族馆喜欢浅滩与其他黑暗的鱼和鱼从苍白的水族馆更喜欢其他苍白的鱼。我们的研究结果是一致的古怪效应的预测，并展示了形态颜色图案的变化和行为的决定如何相互作用，以介导鱼类的反捕食策略。
Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual's risk of predation, for example through predator confusion. Theory predicts that individuals that are different in appearance to the rest of the group are at a greater risk of predation because they are more conspicuous to predators (the ‘oddity’ effect). Thus, animals should choose group mates that are the most similar in appearance to themselves. Another common antipredator tactic is crypsis (camouflage). Fishes are capable of changing colour to match their visual background, but few studies have examined how this might influence shoaling decisions, particularly in the context of the oddity effect. We induced colour pattern changes in a colourful species of freshwater fish, the western rainbowfish, Melanotaenia australis, by maintaining fish in dark and pale aquaria for 2 weeks. Analysis of the proportion of black body pigmentation confirmed that rainbowfish in dark environments developed darker colour patterns than those held in pale environments. We then conducted behavioural observations to determine whether fish subsequently based their shoaling decisions on body coloration. We found that rainbowfish preferred to shoal with similar individuals; fish that had been held in dark aquaria preferred to shoal with other dark fish and fish from pale aquaria preferred other pale fish. Our findings are consistent with the predictions of the oddity effect and demonstrate how morphological colour pattern changes and behavioural decisions interact to mediate antipredator tactics in fish.