Pollen-flowers with heteromorphic stamens have been shown to promote an intrafloral division of labour as a solution to fitness costs arising from pollen consumption by bees, known as the pollen dilemma. Usually, the division is based on morphological differences in anther and pollen traits that correlate with stamen function: pollinating anthers are larger and contain more and higher-quality pollen grains than feeding anthers. Here, we present a new strategy based on a high investment in reward production and thus attraction, in the heterantherous Pterolepis glomerata, to overcome short flower longevity and maintain reproductive success. In P. glomerata small feeding anthers not only produced more pollen grains and more grains with cytoplasmic content, but also released more pollen than pollinating anthers after a single visit. This pattern was consistent until the end of floral anthesis, showing the existence of pollen-dosing mechanisms. Bees equally visited flowers with yellow feeding anthers and pollinating anthers with yellow connective appendages, indicating a visual similarity, as predicted by bee vision modelling. Our results demonstrate that the division of labour might have different outcomes. Instead of the classical expectation of more investment in reproductive pollen in pollinating stamens, P. glomerata invested more in attraction and reward in feeding stamens.

中文翻译：

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对异花花卉分工的新认识：Pterolepis glomerata（Melastomataceae）

已显示具有异型雄蕊的花粉花可以促进花内分工，以解决蜜蜂花粉消耗引起的健身成本问题，这被称为花粉困境。通常，该划分基于与雄蕊功能相关的花药和花粉性状的形态差异：授粉花药比进食花药更大，并且包含更多和更高质量的花粉粒。在这里，我们提出了一项新的战略，该战略基于对奖励生产的巨大投资，从而吸引了异花的翼缘蕨，以克服短花寿命并保持繁殖成功。在P. glomerata较小的饲喂花药不仅会产生更多的花粉粒和更多具有细胞质含量的谷物，而且比单次访花的花粉花药释放出更多的花粉。这种模式一直持续到花粉开花结束，表明存在花粉给药机制。蜜蜂用黄色的喂药花药和带有黄色结缔附属物的授粉花药平均造访花，表明其视觉相似性，这是蜜蜂视觉建模所预测的。我们的结果表明，分工可能会产生不同的结果。相反，在生殖花粉授粉中的雄蕊更多投资的古典期待，P.茅在喂养雄蕊投入了更多的吸引力和奖励。