Zung Jessica L, Kotb Sumer M, McBride Carolyn S
Department of Ecology and Evolutionary Biology and Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA 08544.
bioRxiv. 2023 May 30:2023.05.08.539789. doi: 10.1101/2023.05.08.539789.
The natural world is full of odours-blends of volatile chemicals emitted by potential sources of food, social partners, predators, and pathogens. Animals rely heavily on these signals for survival and reproduction. Yet we remain remarkably ignorant of the composition of the chemical world. How many compounds do natural odours typically contain? How often are those compounds shared across stimuli? What are the best statistical strategies for discrimination? Answering these questions will deliver crucial insight into how brains can most efficiently encode olfactory information. Here, we undertake the first large-scale survey of vertebrate body odours, a set of stimuli relevant to blood-feeding arthropods. We quantitatively characterize the odour of 64 vertebrate species (mostly mammals), representing 29 families and 13 orders. We confirm that these stimuli are complex blends of relatively common, shared compounds and show that they are much less likely to contain unique components than are floral odours-a finding with implications for olfactory coding in blood feeders and floral visitors. We also find that vertebrate body odours carry little phylogenetic information, yet show consistency within a species. Human odour is especially unique, even compared to the odour of other great apes. Finally, we use our newfound understanding of odour-space statistics to make specific predictions about olfactory coding, which align with known features of mosquito olfactory systems. Our work provides one of the first quantitative descriptions of a natural odour space and demonstrates how understanding the statistics of sensory environments can provide novel insight into sensory coding and evolution.
自然界充满了气味——由食物来源、社交伙伴、捕食者和病原体等潜在源头释放的挥发性化学物质的混合体。动物在很大程度上依赖这些信号来生存和繁殖。然而，我们对化学世界的组成仍然知之甚少。天然气味通常包含多少种化合物？这些化合物在不同刺激物之间的共享频率如何？最佳的辨别统计策略是什么？回答这些问题将为大脑如何最有效地编码嗅觉信息提供关键见解。在这里，我们首次对脊椎动物的体臭进行了大规模调查，这些刺激物与吸食血液的节肢动物相关。我们定量表征了64种脊椎动物（主要是哺乳动物）的气味，它们分属于29个科和13个目。我们证实，这些刺激物是相对常见的共享化合物的复杂混合体，并表明它们比花香气味更不可能含有独特成分——这一发现对吸食血液者和访花者的嗅觉编码具有启示意义。我们还发现，脊椎动物的体臭携带的系统发育信息很少，但在一个物种内表现出一致性。人类的气味尤其独特，即使与其他大型猿类的气味相比也是如此。最后，我们利用对气味空间统计的新认识对嗅觉编码做出具体预测，这些预测与蚊子嗅觉系统的已知特征相符。我们的工作提供了对自然气味空间的首批定量描述之一，并展示了理解感官环境的统计数据如何能为感官编码和进化提供新的见解。
