Fukui Shin, Araki Kiwako S
Center for Ecological Research, Kyoto University, Otsu, Shiga, Japan; Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan.
Center for Ecological Research, Kyoto University, Otsu, Shiga, Japan; Department of Biotechnology, Faculty of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan.
PLoS One. 2014 Dec 30;9(12):e116111. doi: 10.1371/journal.pone.0116111. eCollection 2014.
The evolutionary origins and advantages of clonal reproduction relative to sexual reproduction have been discussed for several taxonomic groups. In particular, organisms with a sessile lifestyle are often exposed to spatial and temporal environmental fluctuations. Thus, clonal propagation may be advantageous in such fluctuating environments, for sessile species that can reproduce both sexually and clonally. Here we introduce the concept of niche to a lattice space that changes spatially and temporally, by incorporating the compatibility between the characteristics of a sessile clonal plant with its habitat into a spatially explicit individual-based model. We evaluate the impact of spatially and temporally heterogeneous environments on the evolution of reproductive strategies: the optimal balance between seed and clonal reproduction of a clonal plant. The spatial niche case with local habitats led to avoidance of specialization in reproductive strategy, whereas stable environments or intensive environmental change tended to result in specialization in either clonal or seed reproduction under neutral conditions. Furthermore, an increase in spatial niches made clonal reproduction advantageous, as a consequence of competition among several genets under disturbed conditions, because a ramet reached a favorable habitat through a rare long-distance dispersal event via seed production. Thus, the existence of spatial niches could explain the advantages of clonal propagation.
关于克隆繁殖相对于有性繁殖的进化起源和优势，已经在几个分类群中进行了讨论。特别是，具有固着生活方式的生物经常面临空间和时间上的环境波动。因此，对于既能进行有性繁殖又能进行克隆繁殖的固着物种来说，克隆繁殖在这种波动的环境中可能具有优势。在这里，我们通过将固着克隆植物的特征与其栖息地之间的兼容性纳入一个空间明确的基于个体的模型，将生态位的概念引入到一个随空间和时间变化的格子空间中。我们评估了空间和时间异质环境对繁殖策略进化的影响：克隆植物种子繁殖和克隆繁殖之间的最佳平衡。具有局部栖息地的空间生态位情况导致避免繁殖策略的专业化，而稳定的环境或强烈的环境变化在中性条件下往往导致克隆繁殖或种子繁殖的专业化。此外，空间生态位的增加使克隆繁殖具有优势，这是由于在受干扰条件下几个无性系分株之间的竞争，因为一个分株通过种子生产的罕见长距离扩散事件到达了有利的栖息地。因此，空间生态位的存在可以解释克隆繁殖的优势。
