Morphological correlates of nectar production used by honeybees

1. Honeybees foraging on lavender have been shown to choose inflorescences that are larger and have more flowers. If they are selecting optimally then these inflorescences should yield higher net rates of energy gain. The number and distribution of flowers within inflorescences is a complex function of age, however, which might itself influence nectar quality and availability. 2. Sampling of the overnight nectar secretion of visited and unvisited inflorescences showed that younger inflorescences with more flowers produced more sugar per flower and had fewer unproductive flowers than other inflorescences, but the size of the inflorescence had no effects. 3. Overall display size attracted bees to inspect inflorescences, as inflorescences that were inspected but rejected were larger and/or had larger or more bracts than those that were ignored. Bees, however, accepted more productive inflorescences based on different cues: inflorescence age and number of flowers. 4. Inflorescence choice thus appeared to reflect a two-stage decision process based on different morphological criteria at each stage.