Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa.
Instituto Multidisciplinario de Biología Vegetal (UNC-CONICET), Cordoba, Argentina.
Plant Biol (Stuttg). 2020 Sep;22(5):924-931. doi: 10.1111/plb.13145. Epub 2020 Jul 22.
The large body of work on the adaptation of plants to pollinators is still somewhat incomplete because most studies focus on one-to-one interactions. How will adaptation proceed in a multi-pollinator environment? According to Stebbins' Most Effective Pollinator Principle, 'the characteristics of the flower will be moulded by those pollinators that visit it most frequently and effectively.' To test this hypothesis, we studied the pollination biology of Pelargonium incrassatum (Geraniaceae) in the Namaqualand Region of Southern Africa. This species has a long floral tube and we expected its most important pollinator to have a long proboscis. Contrary to expectations, the most important pollinator was a short proboscid fly (a new species of Prosoeca), while Prosoeca peringueyi, which had a proboscis that matched the floral tube length, was a rare visitor. Consistent with the high degree of trait mismatching, we did not detect selection on tube length at most sites. The paradox of mismatching traits can be resolved by considering the strength of the trade-off involved. Adaptation to the rare species can apparently occur without incurring the cost of reduced pollination by the abundant species. Generally, species may often evolve specialized morphology if they do not incur the cost of ecological specialization.
大量关于植物适应传粉者的研究仍有些不完整，因为大多数研究都集中在一对一的相互作用上。在多传粉者环境中，适应将如何进行？根据斯特宾斯的最有效传粉者原则，“花的特征将由最频繁和有效地访问它的传粉者塑造。”为了检验这一假说，我们研究了南非纳马夸兰地区的天竺葵属植物 Pelargonium incrassatum 的传粉生物学。该物种具有长的花管，我们预计其最重要的传粉者具有长的喙。与预期相反，最重要的传粉者是一种短喙蝇（Prosoeca 的一个新种），而喙与花管长度相匹配的 Prosoeca peringueyi 则是罕见的访客。与高度的特征不匹配一致，我们在大多数地点都没有检测到对管长的选择。通过考虑涉及的权衡强度，可以解决特征不匹配的悖论。对稀有物种的适应显然可以在不减少丰富物种授粉成本的情况下发生。一般来说，如果物种不承担生态专业化的成本，它们可能经常进化出专门的形态。
