Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Higashihiroshima, 739-8528, Japan.
Saijo Ecology Institute, 1387-38 Iida, Hachihonmatsu, Higashihiroshima, 739-0141, Japan.
Sci Rep. 2018 Apr 3;8(1):5516. doi: 10.1038/s41598-018-23917-y.
Certain butterflies utilize plant-acquired alkaloids for their own chemical defense and/or for producing male sex pheromone; a trait known as pharmacophagy. Males of the danaine butterfly, Parantica sita, have been reported to ingest pyrrolizidine alkaloids (PAs) as adults to produce two PA-derived sex pheromone components, viz. danaidone (major) and 7R-hydroxydanaidal. We found, however, that not all PAs that can be precursors for the pheromone serve for mating success of males. Here we show that although the sex pheromone is regarded as a requisite for successful mating, uptake of specific PA(s) (lycopsamine-type PAs) is also imperative for the males to achieve copulation. The increase in the levels of two biogenic amines, octopamine and/or serotonin, in the brain and thoracic ganglia of males fed with specific PA(s) suggested that these alkaloids most likely enhance male mating activity. The results can present new evidence for the evolutionary provenance of pharmacophagous acquisition of PAs in PA-adapted insects.
某些蝴蝶利用植物获得的生物碱来进行自身的化学防御和/或产生雄性性信息素；这种特性被称为取食植物源性生物碱。据报道，大蚕蛾科的 Parantica sita 雄蝶在成虫期会摄入吡咯里西啶生物碱（PAs），以产生两种 PA 衍生的性信息素成分，即 danaidone（主要成分）和 7R-羟基达那依定。然而，我们发现并非所有可作为信息素前体的 PAs 都能提高雄蝶的交配成功率。在这里，我们表明，尽管性信息素被认为是成功交配的必要条件，但特定 PA（lycopsamine 型 PAs）的摄取对于雄蝶实现交配也是至关重要的。摄入特定 PA（s）的雄蝶的脑中及胸部神经节中二种生物胺（章鱼胺和/或血清素）水平的增加表明，这些生物碱很可能增强了雄蝶的交配活动。该结果可为适应 PA 的昆虫中 PA 取食的进化起源提供新的证据。
