Pollinator visitation rate and effectiveness vary with flowering phenology

Premise of the Study – Flowering time may influence pollination success and seed set through a variety of mechanisms, including seasonal changes in total pollinator visitation or the composition and effectiveness of pollinator visitors.

Methods – We investigated mechanisms by which changes in flowering phenology influence pollination and reproductive success of Mertensia ciliata (Boraginaceae). We manipulated flowering onset of potted plants and assessed the frequency and composition of pollinator visitors, as well as seed set. We tested whether floral visitors differed in their effectiveness as pollinators by measuring pollen receipt and seed set resulting from single visits to virgin flowers.

Key Results – Despite a five-fold decrease in pollinator visitation over four weeks, we detected no significant difference in seed set among plants blooming at different times. On a per-visit basis, each bumblebee transferred more conspecific pollen than did a solitary bee or a fly. The pro...

研究前提——开花时间可能通过多种机制影响传粉成功率与结实率，包括传粉者总访花次数的季节性变化，或传粉者群体的组成及其传粉有效性的改变。

方法——我们探究了开花物候变化对紫草科植物Mertensia ciliata传粉及繁殖成功的影响机制。通过调控盆栽植株的开花起始时间，评估传粉者访花的频率与组成，以及结实率。我们通过测量单次访问未受粉花朵后花粉接收量与结实率，验证不同访花者的传粉有效性是否存在差异。

主要结果——尽管四周内传粉者访花次数下降了五倍，但不同开花时间植株的结实率未发现显著差异。单次访花中，熊蜂传递的同种花粉量多于独居蜂或蝇类。此外，……