Data from: Kin recognition in embryonic damselfishes

Predator-induced mortality rates are highest in early life stages; therefore, early recognition of threats can greatly increase survival chances. Some species of coral reef fishes have been frequently found to recruit back to their natal reefs; in this instance, there is a high chance of juveniles encountering their siblings, among other kin, after hatching. Kin recognition plays an important ecological role in that it allows individuals to protect genetically similar relatives, and hence increase their inclusive fitness. By observing changes in heart rates, we demonstrated that embryos of two damselfish species, Acanthochromis polyacanthus and Amphiprion melanopus, not only possess recognition of kin and damage-released alarm odours, but also react to them in a graded manner. Such refined olfactory capabilities in embryonic stage organisms (seven and eleven days after fertilisation) suggest identification of threats may provide survival advantages post-hatching, such as the informed choice of low risk habitats at settlement. To our knowledge this is the first time that kin recognition has been identified in embryos of any species.捕食者诱导的死亡率在生命早期阶段最高；因此，早期识别威胁可大幅提升个体存活概率。已有多项研究发现，部分珊瑚礁鱼类会回迁至其出生的礁盘；在此情境下，幼体孵化后有极高概率与其同胞及其他亲属相遇。亲属识别（kin recognition）在生态系统中发挥着关键作用：它使个体能够保护遗传亲缘关系相近的亲属，进而提升自身的广义适合度（inclusive fitness）。通过观测心率变化，我们证实，两种雀鲷（Acanthochromis polyacanthus与Amphiprion melanopus）的胚胎不仅具备识别亲属与损伤释放的警报气味的能力，还能以分级响应的方式对这些信号作出反应。这些在受精后7天与11天的胚胎阶段就具备的精细嗅觉能力，表明识别威胁可为幼体孵化后的存活带来显著优势，例如在幼体定居阶段自主选择低风险栖息环境。据我们所知，这是首次在任意物种的胚胎中发现亲属识别现象。