The reproduction of many brachyuran crustaceans involves the formation of mating pairs often around the time of the female moult with attraction of a sexual partner and mating behaviour controlled by sex pheromones. In shore crabs, Carcinus maenas, females produce sex pheromones that are released in the urine. High Performance Liquid Chromatography analysis (HPLC) of female urine shows that the pheromone, identified as the nucleotide uridine diphosphate (UDP), elutes as an unresolved peak with structurally related nucleotides. We examined female urine samples over the moult cycle and detected UDP as well as uridine triphosphate (UTP). Bioassays were conducted to establish the possibility of a blend of nucleotides forming a sex pheromone bouquet in C. maenas. Whilst UDP induced the male mate guarding behaviour (cradling), a mixture of the two nucleotides at a ratio of 4:1 UDP:UTP elicited an even stronger mating response than either UDP or UTP individually. The urine concentration and composition of these nucleotides changes over the moult period pre and post ecdysis, providing evidence that a pheromone bouquet composition is not always constant. The change of the bouquet is related to the physiological state of the sender, here the moult cycle. Our study unravels the functionality of reaction-specific molecules in a pheromone bouquet. Whilst UDP is the mating signal, UTP acts as an attractant and combined they maximise the reproductive response. The use of bouquets provides species-specificity, potentially enabling reproductive isolation of sympatric species, and contains valuable information on the physiological state of the sender.

许多短尾甲壳类动物的繁殖涉及通常在雌性换羽期间通过性伴侣的吸引和由性信息素控制的交配行为形成交配对。在岸蟹（Carcinus maenas）中，雌性会产生通过尿液释放的性信息素。女性尿液的高效液相色谱分析 (HPLC) 显示，鉴定为核苷酸尿苷二磷酸 (UDP) 的信息素作为未分离的峰与结构相关的核苷酸洗脱。我们检查了换羽周期内的雌性尿液样本，并检测到 UDP 以及三磷酸尿苷 (UTP)。进行生物测定以确定核苷酸混合物在C. maenas 中形成性信息素花束的可能性. 虽然 UDP 会诱导雄性伴侣守卫行为（抱抱），但 UDP:UTP 比例为 4:1 的两种核苷酸的混合物比单独的 UDP 或 UTP 引起更强烈的交配反应。这些核苷酸的尿液浓度和成分在蜕皮前后的换羽期间会发生变化，这证明信息素花束成分并不总是恒定的。花束的变化与发送者的生理状态有关，这里是换羽周期。我们的研究揭示了信息素花束中反应特异性分子的功能。虽然 UDP 是交配信号，但 UTP 充当引诱剂，并将它们结合起来最大化繁殖反应。花束的使用提供了物种特异性，有可能实现同域物种的生殖隔离，