Section of Neurobiology and Behavior, Cornell University, Seeley G. Mudd Hall, 14853, Ithaca, New York.
J Chem Ecol. 1992 Mar;18(3):427-39. doi: 10.1007/BF00994242.
The olfactory receptor neurons in basiconic sensilla on the antennae ofUtetheisa ornatrix, which, in females, had earlier been shown to be responsive to stimulation with hydroxydanaidal (HD), are here shown to be responsive to volatile substances in samples of pyrrolizidine alkaloids (PAs). These latter substances are secondary plant metabolites present in the host plant of the larvae. Their sequestration during larval life serves to protect all life stages from predation. In males, the PAs also provide precursors for the production of the male pheromone, HD. In females, basiconic receptor neurons begin to respond to stimulus cartridges containing 1 ng of (R)-(-)-hydroxydanaidal, 100 ng of its isomer, (S)-(+)-hydroxydanaidal, and to volatiles emanating from 10μg of the alkaloids monocrotaline and heliotrine. Receptor neurons in males are generally responsive to the same array of substances but with reduced sensitivity. The dietary background of the adult moths with respect to prior ingestion of PAs does not influence the response capabilities of basiconic receptor neurons to HD or to the volatile components of PAs. Earlier studies in another arctiid (Rhodogastria), had indicated that trace amounts of HD are present in PAs, presumably as their hydrolysis product. Thus we assume that, under natural conditions, HD may be an active component of the volatiles from PAs and may serve as both a male pheromone and a kairomone. Sensitivity to HD could thereby provide information about the location and PA content of potential mates and food plants. Mechanisms that may have resulted in the evolution of a signaling system with these properties are discussed.
触角上的锥形感受器上的嗅觉受体神经元对羟二氢野百合碱（HD）刺激有反应，此前研究表明雌性触角上的这些神经元对吡咯里西啶生物碱（PA）的挥发物有反应。这些物质是幼虫的宿主植物中的次生植物代谢物。它们在幼虫生活期间被隔离，以保护所有生命阶段免受捕食。在雄性中，PA 还为雄性信息素 HD 的产生提供前体。在雌性中，锥形受体神经元开始对含有 1ng（R）-（-）-羟二氢野百合碱、100ng 其异构体（S）-（+）-羟二氢野百合碱的刺激盒以及 10μg 单端孢霉烯和海利托林等生物碱的挥发物做出反应。雄性的受体神经元通常对相同的物质阵列有反应，但敏感性降低。成年飞蛾的饮食背景是否以前摄入过 PA，并不影响锥形受体神经元对 HD 或 PA 的挥发性成分的反应能力。之前在另一种夜蛾（Rhodogastria）中的研究表明，痕量的 HD 存在于 PA 中，可能是其水解产物。因此，我们假设在自然条件下，HD 可能是 PA 挥发物的活性成分，可作为雄性信息素和引诱剂。对 HD 的敏感性可以提供有关潜在配偶和食物植物的位置和 PA 含量的信息。讨论了可能导致具有这些特性的信号系统进化的机制。
