Faculty of Environmental, Life, Natural Science and Technology, Okayama University, Tsushima-Naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan.
Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Kobe, 657-8501, Japan.
Oecologia. 2024 Oct;206(1-2):37-45. doi: 10.1007/s00442-024-05607-x. Epub 2024 Aug 22.
Reproductive interference is defined as an interspecific interaction that reduces fitness via mating processes. Although its ecological and evolutionary consequences have attracted much attention, how reproductive interference affects the population genetic structures of interacting species is still unclear. In flowering plants, recent studies found that self-pollination can mitigate the negative effects of reproductive interference. Selfing-biased seed production is expected to increase population-level inbreeding and the selfing rate, and limits gene flow via pollinator outcrossing among populations. We examined the population genetics of the mixed-mating annual herb Commelina communis f. ciliata, focusing on reproductive interference by the sympatric competing congener C. communis using microsatellite markers. First, we found that almost all C. c. f. ciliata populations had relatively high inbreeding coefficients. Then, comparing sympatric and allopatric populations, we found evidence that reproductive interference from a competing congener increased the inbreeding coefficient and selfing rate. Allopatric populations exhibit varied selfing rates while almost all sympatric populations exhibit extremely high selfing rates, suggesting that population selfing rates were also influenced by unexamined factors, such as pollinator limitation. Besides, our findings revealed that reproductive interference from a competing congener did not limit gene flow among populations. We present the first report on how reproductive interference affects the genetic aspects of populations. Our results suggested that the high selfing rate of C. c. f. ciliata promotes its sympatric distribution with C. communis, even in the presence of reproductive interference, although it is not clear whether reproductive interference directly causes the high selfing rate.
生殖干扰被定义为一种通过交配过程降低适合度的种间相互作用。尽管其生态和进化后果引起了广泛关注，但生殖干扰如何影响相互作用物种的种群遗传结构仍不清楚。在开花植物中，最近的研究发现自交可以减轻生殖干扰的负面影响。偏向自交的种子生产预计会增加种群水平的近亲繁殖和自交率，并通过传粉者在种群间的异交来限制基因流。我们研究了一年生草本植物鸭跖草的混合交配种群遗传学，重点关注同域竞争近缘种鸭跖草的生殖干扰，使用微卫星标记。首先，我们发现几乎所有的鸭跖草 f. ciliata 种群都具有相对较高的近交系数。然后，通过比较同域和异域种群，我们发现有证据表明，来自竞争近缘种的生殖干扰增加了近交系数和自交率。异域种群表现出不同的自交率，而几乎所有同域种群都表现出极高的自交率，这表明种群自交率也受到未被研究的因素的影响，例如传粉者限制。此外，我们的研究结果表明，来自竞争近缘种的生殖干扰并没有限制种群间的基因流。这是首次报道生殖干扰如何影响种群的遗传方面。我们的研究结果表明，鸭跖草 f. ciliata 的高自交率促进了它与鸭跖草的同域分布，即使在存在生殖干扰的情况下也是如此，尽管还不清楚生殖干扰是否直接导致了高自交率。
