Pheromones regulating mating behavior are diverse in structure and typically show high species specificity. However, depending on their information content they can also be quite conserved across species. Here, we demonstrate that methyl geranate, an anti-aphrodisiac produced during brood care, is a conserved volatile organic compound within the genus Nicrophorus (burying beetles). Burying beetles are well known for their elaborate biparental care. They reproduce on small vertebrate carcasses and typically it is a pair of beetles, a male and a female, which cooperate in feeding and defending their young. During the intensive period of parental care, female Nicrophorus vespilloides have been shown to emit a volatile substance, methyl geranate, which acts as an anti-aphrodisiac and deters males from copulating. Methyl geranate is biosynthetically linked to juvenile hormone III, a hormone mediating a temporary infertility in this species. By investigating volatile emission of seven geographically and phylogenetically distinct burying beetle species, we provide evidence that methyl geranate is a conserved substance released by parenting adults throughout the genus. We, furthermore, show that there is high quantitative variation (1) between species, which can partly be explained by species differences in body size and (2) within species, which can be attributed to sex differences and individual brood size differences. Moreover, we demonstrate that a species of the genus Ptomascopus, which is closely related to Nicrophorus, but shows no elaborate post-hatching parental behavior, emits only trace amounts of methyl geranate during breeding. Our results, therefore, suggest that the synthesis of an anti-aphrodisiac was an important step in the evolution of concerted parental care in burying beetles. However, behavioral experiments are needed to further corroborate our hypothesis.

中文翻译：

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在掩埋的甲虫中，保护父母的信息素是进化保守的（Silphidae：Nicrophorus）

调节交配行为的信息素结构多样，通常显示出很高的物种特异性。但是，根据它们的信息内容，它们在整个物种中也可以非常保守。在这里，我们证明了香叶酸甲酯，一种在育雏过程中产生的抗壮阳药，是Nicrophorus属（埋藏的甲虫）中一种保守的挥发性有机化合物。埋葬甲虫以其精心的双亲照顾而闻名。它们在小型脊椎动物尸体上繁殖，通常是一对甲虫，一种雄性和一种雌性，它们共同喂养和保卫它们的幼体。在重症监护期间，雌性Nicrophorus vespilloides现已显示出会散发挥发性物质香叶酸甲酯，可起到抗壮阳药的作用，并阻止雄性交配。香叶酸甲酯与幼年激素III（一种介导该物种暂时性不育的激素）生物合成相连。通过调查七个地理和系统发育上不同的埋藏甲虫物种的挥发性排放物，我们提供了证据，即香叶草酸甲酯是养育成年成虫在整个属中释放的保守物质。此外，我们还表明，物种之间存在高度的数量变化（1），这在一定程度上可以通过体型上的物种差异和物种内的（2）来解释，这可以归因于性别差异和个体育雏尺寸差异。此外，我们证明了Ptomascopus属，与Nicrophorus密切相关，但在孵化后并未表现出复杂的父母行为，在繁殖过程中仅散发痕量的香叶酸甲酯。因此，我们的研究结果表明，抗春药的合成是掩埋甲虫过程中父母共同监护的重要一步。但是，需要进行行为实验以进一步证实我们的假设。