Smithsonian Tropical Research Institute, Panama City, Panama.
Museum of Comparative Zoology, Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA, USA.
Commun Biol. 2020 Dec 9;3(1):749. doi: 10.1038/s42003-020-01482-3.
Plants and their specialized flower visitors provide valuable insights into the evolutionary consequences of species interactions. In particular, antagonistic interactions between insects and plants have often been invoked as a major driver of diversification. Here we use a tropical community of palms and their specialized insect flower visitors to test whether antagonisms lead to higher population divergence. Interactions between palms and the insects visiting their flowers range from brood pollination to florivory and commensalism, with the latter being species that feed on decaying-and presumably undefended-plant tissues. We test the role of insect-host interactions in the early stages of diversification of nine species of beetles sharing host plants and geographical ranges by first delimiting cryptic species and then using models of genetic isolation by environment. The degree to which insect populations are structured by the genetic divergence of plant populations varies. A hierarchical model reveals that this variation is largely uncorrelated with the kind of interaction, showing that antagonistic interactions are not associated with higher genetic differentiation. Other aspects of host use that affect plant-associated insects regardless of the outcomes of their interactions, such as sensory biases, are likely more general drivers of insect population divergence.
植物及其专门的花访客为物种相互作用的进化后果提供了有价值的见解。特别是，昆虫与植物之间的对抗性相互作用经常被认为是多样化的主要驱动因素。在这里，我们使用热带棕榈植物及其专门的昆虫花访客群落来检验对抗性是否会导致更高的种群分歧。棕榈植物与访问其花朵的昆虫之间的相互作用范围从育雏授粉到花食性和共生，后者是指以腐烂且（据推测）无防御性的植物组织为食的物种。我们通过首先确定隐种，然后使用环境遗传隔离模型，检验了在分享宿主植物和地理范围的九种甲虫的早期多样化过程中昆虫 - 宿主相互作用的作用。昆虫种群受植物种群遗传分歧结构的程度各不相同。分层模型表明，这种变异与相互作用的类型基本没有相关性，表明对抗性相互作用与更高的遗传分化无关。其他方面的宿主利用，无论其相互作用的结果如何，都会影响与植物相关的昆虫，例如感官偏差，更可能是昆虫种群分化的更普遍驱动因素。
