School of Plant Protection, Nanjing Agricultural University, No. 1 Weigang, Nanjing, 210095, Jiangsu, China.
Laboratory of Fundamental and Applied Research in Chemical Ecology (FARCE), Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland.
J Chem Ecol. 2020 Feb;46(2):128-137. doi: 10.1007/s10886-019-01142-9. Epub 2020 Jan 6.
Cuticular compounds (CCs) that cover the surface of insects primarily serve as protection against entomopathogens, harmful substances, and desiccation. However, CCs may also have secondary signaling functions. By studying the role of CCs in intraspecific interactions, we may advance our understanding of the evolution of pheromonal communication in insects. We previously found that the gregarious parasitoid, Cotesia glomerata (L.), uses heptanal as a repellent pheromone to help avoid mate competition among sibling males, whereas another cuticular aldehyde, nonanal, is part of the female-produced attractive sex pheromone. Here, we show that the same aldehydes have different pheromonal functions in a related solitary parasitoid, Cotesia marginiventris (Cresson). Heptanal enhances the attractiveness of the female's sex pheromone, whereas nonanal does not affect a female's attractiveness. Hence, these common aldehydes are differentially used by the two Cotesia species to mediate, synergistically, the attractiveness of the main constituents of their respective sex pheromones. The specificity of the complete sex pheromone blend is apparently regulated by two specific, less volatile compounds, which evoke strong electroantennographic (EAG) responses. This is the first demonstration that volatile CCs have evolved distinct pheromonal functions to aid divergent mating strategies in closely related species. We discuss the possibility that additional compounds are involved in attraction and that, like the aldehydes, they are likely oxidative products of unsaturated cuticular hydrocarbons.
表皮化合物（CCs）覆盖在昆虫表面，主要起到保护作用，防止昆虫受到病原体、有害物质和干燥的侵害。然而，CCs 也可能具有次要的信号功能。通过研究 CCs 在种内相互作用中的作用，我们可以深入了解昆虫信息素通讯的进化。我们之前发现群居性寄生蜂 Cotesia glomerata（L.）使用庚醛作为驱避信息素来帮助避免同胞雄性之间的交配竞争，而另一种表皮醛，壬醛，是雌性产生的有吸引力的性信息素的一部分。在这里，我们表明，相同的醛在相关的独居寄生蜂 Cotesia marginiventris（Cresson）中具有不同的信息素功能。庚醛增强了雌性性信息素的吸引力，而壬醛则不影响雌性的吸引力。因此，这两种 Cotesia 物种通过协同作用，以不同的方式使用这些常见的醛来调节各自性信息素主要成分的吸引力。完整性信息素混合物的特异性显然是由两种特定的、挥发性较低的化合物调节的，这两种化合物会引起强烈的触角电生理（EAG）反应。这是第一个证明挥发性 CCs 已经进化出不同的信息素功能，以帮助相关物种中不同的交配策略的例子。我们讨论了其他化合物可能参与吸引的可能性，并且，与醛类似，它们可能是不饱和表皮碳氢化合物的氧化产物。
