List of species from Delayed fertilization facilitates flowering time diversity in Fagaceae

Fagaceae includes typical masting species that exhibit highly synchronized and fluctuating acorn production. Fagaceae shows an interesting feature in that fertilization is delayed by several weeks to more than 1 year after pollination. Although delayed fertilization was recorded over a century ago, the evolutionary advantage of delayed fertilization is still poorly understood. Here, we present a new hypothesis that delayed fertilization facilitates temporal niche differentiation via non-overlapping flowering times among species. Comparing flowering and fruiting times in 228 species from five genera in Fagaceae, we first show that there is a close association between a wider spread of flowering times and the likelihood of a 2-year fruiting habit in which there is a long delay from pollination to fertilization. To study the coevolution of flowering time and delayed fertilization, we developed a mathematical model that incorporates the effects of competition for pollinators, seed predator satiation and unfavourable season for reproduction on fitness. The model shows that delayed fertilization facilitates the diversification of flowering time in a population, which is advantageous for animal-pollinated trees that compete over pollinators. Our new hypothesis about the coevolution of delayed fertilization and flowering time will provide new insight into the evolution of masting.This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

壳斗科中包含典型的结实植物，其橡实产量表现出高度同步和波动的特性。壳斗科在繁殖方面呈现一独特特征，即受粉后的授精过程被延迟数周至一年以上。尽管延迟授精现象在一百多年前就已记录，但其进化优势仍鲜为人知。本研究提出一种新假说，即延迟授精通过物种间开花时间的非重叠性，促进了时空生态位分化。通过对壳斗科五属228个物种的开花和结实时间进行比较，我们首先揭示了开花时间分布范围的广泛性与两年结实习性（从受粉到授精之间存在长期延迟）之间的密切关联。为研究开花时间与延迟授精的协同进化，我们开发了一个数学模型，该模型综合考虑了竞争授粉者、种子捕食者饱足程度及不利于繁殖的季节对生物适应性的影响。模型显示，延迟授精促进了种群内开花时间的多样化，这对依赖授粉者进行繁殖的动物传粉树具有竞争优势。关于延迟授精与开花时间协同进化的新假说，将为理解结实植物的进化提供新的视角。本文为特刊‘植物同步种子生产生态与进化’主题的一部分。