Abstract

Many spider crabs attach various kinds of living material to camouflage themselves and thereby escape detection by predators. This strategy uses a suite of co-evolved characters including a pyriform carapace shape, long agile chelipeds, hooked setae and a stereotyped behaviour pattern which is used to gather and plant pieces of other organisms amongst hooked setae on their body. Notomithrax ursus (Herbst, 1788) is a New Zealand majid crab that lives amongst seaweeds and mainly masks itself with the same. In doing so, it uses all the skills that we expect of a dressmaker. Denuded of its mask, the crab chooses algae it can manipulate, measures and cuts each piece, passes them to its mouth, and then plants them on its body in a roughly regular order, such that the severed ends are inserted into the hooked setae with only intact end visible. Longer pieces are planted on the body and smaller pieces on its walking legs to make a profile resembling a clump of seaweed. Distribution of the seaweed follows the distribution of the hooked setae on the crab. The number of pieces attached is independent of crab size and, as carapace width increases, the crabs compensate by cutting out longer pieces of seaweed. Cheliped allometry explains scaling of the mask. Total length of seaweed used can range 0.6–2.6 m (mean 1.36 m). Increasing mask load is accompanied by increases in the number and size of hooked setae thereby strengthening attachment. The behaviour of N. ursus should be called “dressmaking” not “decorating.” It uses a stereotyped behaviour pattern to follow a design, dictated by the distribution of hooked setae, and produce a customized garment concealing it from predators. A hypothesis on the evolution of masking, from passive to active camouflage is proposed, based on the original ideas of C.W.S. Aurivillius.

中文翻译：

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掩盖蟹的伪装，Notomithrax ursus（赫伯斯特，1788年）（十足动物：布拉奇拉：Majidae）：是装饰员还是裁缝？

摘要

许多蜘蛛蟹会附上各种各样的生物材料来伪装自己，从而逃避了掠食者的发现。该策略使用了一组共同​​进化的角色，包括一个梨形甲壳形状，长而敏捷的鹅掌ed，钩状刚毛和定型的行为模式，该行为模式用于在其钩状刚毛中收集和种植其他生物体。猪肺thr（Herbst，1788）是一种新西兰majid蟹，生活在海藻中，主要用海藻掩盖自身。这样，它将使用我们期望的裁缝师所有技能。螃蟹被剥夺了面具，选择可以操纵，测量和切割的藻类，将它们传递到嘴中，然后以大致规则的顺序将其种植在其身上，以便将切断的末端插入钩状的刚毛中。仅完整的末端可见。较长的植物被植入到身体上，而较小的植物被植入在步行的腿上，从而形成类似于一团海藻的轮廓。海藻的分布遵循钩状刚毛在蟹上的分布。附着的鱼片数量与蟹的大小无关，并且随着甲壳宽度的增加，蟹会通过切出更长的海藻来进行补偿。倾斜的倾斜度说明了蒙版的缩放比例。所用海藻的总长度为0.6-2.6 m（平均1.36 m）。面罩负荷的增加伴随着钩状刚毛的数量和大小的增加，从而增强了附着力。的行为猪笼草应被称为“制衣”而不是“装饰”。它使用定型的行为模式来遵循设计，这取决于钩状刚毛的分布，并制作出可将其隐藏在掠食者面前的定制服装。基于CWS Aurivillius的原始思想，提出了关于掩蔽从被动伪装到主动伪装演变的假设。