Middlebury College, Biology Department, Middlebury, Vermont 05753 USA.
Am J Bot. 2002 Mar;89(3):433-40. doi: 10.3732/ajb.89.3.433.
Flowers that are open for >12 h may be visited by both diurnal and nocturnal pollinators. I compared the effectiveness (measured as seed production and pollen movement distance) of diurnal and nocturnal pollinators of Silene alba, a species whose flowers open in evening but close by midmorning the following day. By bagging flowers either during evening hours or during daylight hours or both day and night, I compared seed production caused by diurnal and nocturnal pollinators. Flowers exposed only to nocturnal visitors (mostly sphingid and noctuid moths) produced significantly more seeds than flowers exposed only to diurnal visitors (bees, flies, and wasps). Fluorescent dye applied to anthers moved significantly further and to more stigmas at night than during the day. In both measures of pollination effectiveness, nocturnal-visiting moths are better pollinators of S. alba than are the diurnal-visiting bees, flies, and wasps. These data support the hypothesis that floral phenology is an adaptation to expose flowers to the most effective pollinators.
花期超过 12 小时的花朵可能会同时被昼行性和夜行性传粉者访问。我比较了阿尔卑斯矢车菊（Silene alba）的昼行性和夜行性传粉者的效率（以种子产量和花粉移动距离来衡量），这种花在傍晚开放，但第二天上午中旬就会关闭。我通过在傍晚、白天或昼夜时段给花朵套袋，比较了昼行性和夜行性传粉者引起的种子产量。只暴露于夜行性访客（主要是鳞翅目和夜蛾科的蛾类）的花朵产生的种子明显多于只暴露于昼行性访客（蜜蜂、苍蝇和黄蜂）的花朵。施加在花粉上的荧光染料在夜间比在白天移动得更远，到达的柱头也更多。在这两种授粉效率的衡量标准中，夜行性访花的蛾类比昼行性访花的蜜蜂、苍蝇和黄蜂更能有效地为阿尔卑斯矢车菊授粉。这些数据支持了这样一种假设，即花的物候是一种适应，使花朵暴露于最有效的传粉者。
