Limited phenological and pollinator-mediated isolation among selfing and outcrossing Arabidopsis lyrata populations
Limited phenological and pollinator-mediated isolation among selfing and outcrossing Arabidopsis lyrata populations
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DOI：
10.1098/rspb.2020.2323
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发表时间：
2020-11-25
影响因子：
4.7
通讯作者：
Stift, Marc
中科院分区：
文献类型：
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作者：
Gorman, Courtney E.;Bond, Lindsay;Stift, Marc
从异型杂交到自交的转变是植物中常见的进化转变，并且显然在物种分化中发挥着作用。然而，关于自交进化过程中生殖隔离的最初机制基础仍然存在许多问题。例如，合子前授粉机制（例如物候变化和传粉者访视）对于维持新出现的自交种群与其异交祖先之间的生殖隔离有多重要？为了测试物候和传粉媒介访问的变化是否将拟南芥自交种群与异交种群分离，我们对来自自交和异交种群的植物及其种群间杂种进行了共同的花园实验。具体来说，我们询问异交和自交植物及其群体间杂种之间是否存在通过以下方面的差异进行的隔离：（1）开花的时间或强度；和/或 (2) 授粉媒介拜访。我们发现异交和自交种群的植物之间物候在很大程度上重叠。与交配系统相关的传粉者偏好也没有差异。此外，传粉者更喜欢拜访同一株植物上的花朵，而不是探索附近的植物，这为自花受精创造了很大的机会。总体而言，这表明合子前的预授粉机制并未将植物与拟南芥自交和异交种群强烈地生殖隔离。
Transitions from outcrossing to selfing have been a frequent evolutionary shift in plants and clearly play a role in species divergence. However, many questions remain about the initial mechanistic basis of reproductive isolation during the evolution of selfing. For instance, how important are pre-zygotic pre-pollination mechanisms (e.g. changes in phenology and pollinator visitation) in maintaining reproductive isolation between newly arisen selfing populations and their outcrossing ancestors? To test whether changes in phenology and pollinator visitation isolate selfing populations of Arabidopsis lyrata from outcrossing populations, we conducted a common garden experiment with plants from selfing and outcrossing populations as well as their between-population hybrids. Specifically, we asked whether there was isolation between outcrossing and selfing plants and their between-population hybrids through differences in (1) the timing or intensity of flowering; and/or (2) pollinator visitation. We found that phenology largely overlapped between plants from outcrossing and selfing populations. There were also no differences in pollinator preference related to mating system. Additionally, pollinators preferred to visit flowers on the same plant rather than exploring nearby plants, creating a large opportunity for self-fertilization. Overall, this suggests that pre-zygotic pre-pollination mechanisms do not strongly reproductively isolate plants from selfing and outcrossing populations of Arabidopsis lyrata.