Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany; email:
Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena 07745, Germany; email:
Annu Rev Entomol. 2022 Jan 7;67:201-219. doi: 10.1146/annurev-ento-061421-063433. Epub 2021 Oct 4.
Beetles are hosts to a remarkable diversity of bacterial symbionts. In this article, we review the role of these partnerships in promoting beetle fitness following a surge of recent studies characterizing symbiont localization and function across the Coleoptera. Symbiont contributions range from the supplementation of essential nutrients and digestive or detoxifying enzymes to the production of bioactive compounds providing defense against natural enemies. Insights on this functional diversity highlight how symbiosis can expand the host's ecological niche, but also constrain its evolutionary potential by promoting specialization. As bacterial localization can differ within and between beetle clades, we discuss how it corresponds to the microbe's beneficial role and outline the molecular and behavioral mechanisms underlying symbiont translocation and transmission by its holometabolous host. In reviewing this literature, we emphasize how the study of symbiosis can inform our understanding of the phenotypic innovations behind the evolutionary success of beetles.
甲虫是多种多样细菌共生体的宿主。在本文中，我们综述了这些共生关系的作用，最近的研究描绘了鞘翅目甲虫中共生体的定位和功能，为我们提供了新的认识。共生体的贡献范围从补充必需的营养物质、消化或解毒酶，到产生具有生物活性的化合物，为抵御天敌提供防御。对这种功能多样性的深入了解强调了共生关系如何通过扩大宿主的生态位来促进其进化潜力，但也通过促进专业化来限制其进化潜力。由于细菌在甲虫类群内部和之间的定位可能不同，我们讨论了它如何与微生物的有益作用相对应，并概述了其完全变态宿主中转录和传递共生体的分子和行为机制。在回顾这些文献时，我们强调了共生关系的研究如何为我们理解甲虫进化成功背后的表型创新提供信息。
