Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S3B2
Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
Biol Lett. 2018 Nov 28;14(11):20180616. doi: 10.1098/rsbl.2018.0616.
How does mutualism affect range expansion? On the one hand, mutualists might thrive in new habitats thanks to the resources, stress tolerance or defence provided by their partners. On the other, specialized mutualists might fail to find compatible partners beyond their range margins, limiting further spread. A recent global analysis of legume ranges found that non-symbiotic legumes have been successfully introduced to more ranges than legumes that form symbioses with rhizobia, but there is still abundant unexplained variation in introduction success within symbiotic legumes. We test the hypothesis that generalist legumes have spread to more ranges than specialist legumes. We used published data and rhizobial 16S rRNA sequences from GenBank to quantify the number of rhizobia partners that associate with 159 legume species, spanning the legume phylogeny and the globe. We found that generalist legumes occur in more introduced ranges than specialist legumes, suggesting that among mutualists, specialization hinders range expansions.
互利共生如何影响分布范围的扩张？一方面，由于合作伙伴提供的资源、耐受压力或防御，互利共生体可能在新栖息地中茁壮成长。另一方面，专门的互利共生体可能无法在其分布范围的边缘之外找到兼容的伙伴，从而限制了进一步的扩散。最近对豆科植物分布范围的全球分析发现，与与根瘤菌形成共生关系的豆科植物相比，非共生豆科植物已成功引入更多的分布范围，但共生豆科植物的引入成功率仍存在大量未解释的差异。我们检验了以下假设：即广适性豆科植物的分布范围比专性豆科植物更广。我们使用已发表的数据和 GenBank 中的根瘤菌 16S rRNA 序列，定量了 159 种豆科植物与根瘤菌伙伴的数量，这些豆科植物跨越了豆科植物的系统发育和全球范围。我们发现，广适性豆科植物比专性豆科植物出现在更多的引入分布范围中，这表明在互利共生体中，专业化会阻碍分布范围的扩张。
