Novel nectar robbing negatively affects reproduction in Digitalis purpurea

With many plant-pollinator interactions undergoing change as species’ distributions shift, we require a better understanding of how the addition of new interacting partners can affect plant reproduction. One such group of floral visitors, nectar robbers, can deplete plants of nectar rewards without contributing to pollination. The addition of nectar robbing to the floral visitor assemblage could therefore have costs to the plant´s reproductive output. We focus on a recent plant colonist, Digitalis purpurea, a plant that in its native range is rarely robbed, but experiences intense nectar robbing in areas it has been introduced to. Here, we test the costs to reproduction following experimental nectar robbing. To identify any changes in the behaviour of the principal pollinators in response to nectar robbing, we measured visitation rates, visit duration, proportion of flowers visited and rate of rejection of inflorescences. To find the effects of robbing on fitness, we used proxies for fe...随着物种分布范围发生变迁，诸多植物-传粉者互作关系也随之改变，我们亟需更深入地理解新增互作伙伴如何影响植物的繁殖过程。其中一类访花生物即盗蜜者（nectar robbers），可在不参与传粉的前提下耗尽植物的花蜜资源。因此，在访花生物类群中引入盗蜜行为，可能会对植物的繁殖产出带来负面影响。 本研究以新近定植的植物洋地黄（Digitalis purpurea）为研究对象：该物种在原生分布区内极少遭遇盗蜜，但在其被引入的区域中却面临严重的盗蜜问题。本研究通过实验性盗蜜处理，探究盗蜜对植物繁殖带来的代价。为明确主要传粉者的行为是否会因盗蜜发生改变，我们测定了访花频率、单次访花时长、被访花占比以及花序拒访率。为探究盗蜜对植物适合度的影响，我们采用了适合度替代指标——