Silva Diogo Jackson Aquino, Powell Samuel Bear, Erickson Marilia Fernandes, Cortesi Fabio, Pessoa Daniel Marques Almeida, Cheney Karen Louise
Department of Physiology and Behavior, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
School of the Environment, The University of Queensland, Brisbane, Queensland, Australia.
Biol Lett. 2025 Jun;21(6):20240694. doi: 10.1098/rsbl.2024.0694. Epub 2025 Jun 18.
Conspicuous coloration in body parts that can be autotomized, diverting predator attacks from vital to non-vital regions, is called deflection. Fiddler crabs typically have a cryptic or conspicuous carapace (vital area), while the claw (non-vital) is often conspicuous and used for social communication. Here, we tested whether the conspicuous claws of fiddler crabs divert predator attacks away from their carapaces, enhancing survival. To do this, we used a robotic crab model that replicated the colours and reproductive waving display of the two-toned fiddler crab, . Models were placed in the field to be attacked by Australian brush-turkeys, . We analysed whether the first attack was directed at the claw or the carapace with differently coloured models. Our results show that robot crab models with conspicuous claws drew half of the attacks to the claw, whereas models with non-conspicuous claws were attacked predominately on the carapace. This suggests that the claws of the fiddler crabs effectively attract attacks away from the carapace, functioning as a deflection mechanism. This is the first study demonstrating a claw-deflection strategy in crustaceans, indicating that the claw not only plays a role in intraspecific signalling but also mitigates associated predation risks.
身体上可自割的部位呈现出醒目的颜色，将捕食者的攻击从重要部位转移到非重要部位，这种现象被称为转移。招潮蟹通常具有隐蔽或醒目的头胸甲（重要部位），而螯（非重要部位）往往很显眼，用于社交交流。在此，我们测试了招潮蟹显眼的螯是否能将捕食者的攻击从它们的头胸甲转移开，从而提高存活率。为此，我们使用了一个机器蟹模型，它复制了双色招潮蟹的颜色和求偶挥舞展示。将模型放置在野外，让澳大利亚丛冢雉进行攻击。我们分析了不同颜色模型的首次攻击是针对螯还是头胸甲。我们的结果表明，螯显眼的机器蟹模型吸引了一半的攻击指向螯，而螯不显眼的模型主要受到对头胸甲的攻击。这表明招潮蟹的螯有效地将攻击从其头胸甲吸引开，起到了转移机制的作用。这是第一项证明甲壳类动物存在螯转移策略的研究，表明螯不仅在种内信号传递中起作用，还能降低相关的捕食风险。
