Males of the hermit crab Pagurus filholi perform assessment behavior toward females, as a preliminary step of precopulatory guarding, during the reproductive season. It is known that such behavior is elicited by female sex pheromones, but the compounds involved have never been characterized in this species. Several experiments were conducted to develop a reliable bioassay along with purification procedures to identify potential compounds with pheromonal activity in Pagurus filholi. We developed a bioassay protocol to assess pheromonal activity by using an empty shell with cotton containing either artificial seawater (control) or test water. We measured and compared the time duration of male assessment behavior toward each shell if the test water contained female sex pheromones. Ultra-filtering of seawater samples potentially containing pheromones showed that the compound was <1 kDa in molecular weight. Males showed precopulatory assessment behavior toward “female conditioned” water samples treated with open column purification and eluted with MeOH, suggesting that compounds triggering male behavior were low polar molecules. Molecules with pheromonal activity were not volatile after freeze drying, effective even after heating to 90 °C, and remained active in seawater at 12 °C even after 6 days from sample collection, which suggests a rather stable characteristic of the female sex pheromones of this species.

中文翻译：

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寄居蟹Pagurus filholi雌性信息素的行为分析和化学特征

寄居蟹 Pagurus filholi 的雄性寄居蟹会在繁殖季节对雌性进行评估行为，作为交配前保护的初步步骤。众所周知，这种行为是由雌性性信息素引起的，但所涉及的化合物从未在该物种中得到表征。进行了多项实验以开发可靠的生物测定以及纯化程序，以鉴定在 Pagurus filholi 中具有信息素活性的潜在化合物。我们开发了一种生物测定协议，通过使用含有人工海水（对照）或测试水的棉花空壳来评估信息素活性。如果测试水中含有雌性性信息素，我们测量并比较了雄性评估行为对每个壳的持续时间。对可能含有信息素的海水样品进行超滤显示，该化合物的分子量小于 1 kDa。雄性对用开柱纯化处理并用 MeOH 洗脱的“雌性调节”水样表现出预交配评估行为，这表明触发雄性行为的化合物是低极性分子。具有信息素活性的分子在冷冻干燥后不挥发，即使加热到 90°C 也有效，并且即使在样品采集 6 天后仍然在 12°C 的海水中保持活性，这表明该雌性信息素具有相当稳定的特征。物种。表明触发男性行为的化合物是低极性分子。具有信息素活性的分子在冷冻干燥后不挥发，即使加热到 90°C 也有效，并且即使在样品采集 6 天后仍然在 12°C 的海水中保持活性，这表明该雌性信息素具有相当稳定的特征。物种。表明触发男性行为的化合物是低极性分子。具有信息素活性的分子在冷冻干燥后不挥发，即使加热到 90°C 也有效，并且即使在样品采集 6 天后仍然在 12°C 的海水中保持活性，这表明该雌性信息素具有相当稳定的特征。物种。