| Popis: |
The dying of bumblebees under the late flowering lime tree Tilia tomentosa has been described by several authors. The flowers produce high quantities of non-toxic nectar, and honeybees as well as bumblebees forage on this source. However, only numerous dead bumblebees are found under silver linden trees. In this study the foraging pattern of honeybees and bumblebees on early and late blooming lime trees was compared. Flower visity, nectar availability and the fallout of dead bees was recorded over the course of the day and also during the entire blooming period. Honeybees foraged on T tomentosa only at times of high nectar availability. Bumblebees however visited the trees throughout the flowering season, especially at the beginning, but continued also after decline of nectar production. The different foraging strategies of Bombus and Apis bees are discussed and may explain the phenomenon of dying bumblebees. |
