Visually mediated neighbour recognition in the fiddler crab Uca capricornis

Mating signals are often directed at numerous senses, and provide information about species identity, gender, receptiveness, individual identity and mate quality. Given the diversity of colourful body patterns in invertebrates, surprisingly few studies have examined the role of these visual signals in mate recognition. This experiment demonstrates that distinct carapace colour patterns in the fiddler crab, Uca capricornis, enable males to discriminate between their female neighbours and unfamiliar females.The experiment was conducted in the East Point Reserve, Darwin, NT from September to January 2003 and 2004. The methodology involved identifying male and female U.capricornis neighbours living 10-30cm apart. The female was caught and randomly assigned to one of seven treatments, including replacement with a similar sized female, and various manipulations to alter her appearance. The female was then tethered close to the males burrow and the interaction monitored. The males behaviour was classified as either 'approach' or 'ignore.' The results show that males tended to approach unfamiliar females tethered nearby, whereas they were more likely to ignore their unaltered neighbours tethered in the same position.

求偶信号通常作用于多种感官，可传递物种识别、性别、交配接受度、个体身份以及配偶质量等相关信息。鉴于无脊椎动物拥有丰富多样的色彩体表模式，却鲜有研究探讨此类视觉信号在配偶识别中的作用，此现象颇为出人意料。本实验证实，招潮蟹（Fiddler Crab）物种角眼招潮蟹（Uca capricornis）独特的甲壳体色模式（carapace colour patterns），能够帮助雄性个体区分其邻近的雌性同类与陌生雌性。本实验于2003年至2004年的9月至次年1月，在北领地（NT）达尔文市的东点保护区（East Point Reserve）开展。实验流程包括确定彼此间距为10至30厘米的角眼招潮蟹雌雄邻体。研究人员捕获雌性个体后，将其随机分配至7组处理方案之一，处理方式包括替换为体型相近的雌性个体，以及通过多种操作手段改变其外观形态。随后将该雌性个体栓系于雄性洞穴附近，并对二者的互动行为进行监测。雄性的行为被划分为“趋近”与“无视”两类。实验结果显示，雄性个体更倾向于趋近栓系在附近的陌生雌性，而对栓系于同一位置的未经过人工处理的邻近雌性，则更可能采取无视态度。