Flower Switching during Consecutive Foraging Trips of Bombus ardens Workers (Hymenoptera : Apidae)

概要

論文の詳細を見る
Bumble bees constantly visit plant species of the most rewarding flowers recognized by learning, majors, and rarely visit other flowering species, minors. Majors are thought to be switched as their rewards decrease. This foraging system suggests that the reward collection rate is related with major-switching. To test this prediction, we observed 14 series of foraging trips of Bombus ardens in a forest habitat and monitored 193 trips of eight workers in 122-h observation. We measured weight of load gain and duration of trips, and examined taxonomic make-up of collected pollen grains. The examined pollen belonged to 27 plant species, and 15 species were regarded as majors because their pollen grains were most abundant in pollen loads. We also confirmed flower visitation to most of the majors in the foraging area. In 23 of 50 observed cases of major-switching, bumble bees switched back to the latest majors. This result indicates repeated switching between limited plant taxa. The load gain rate was not correlated with similarity of taxonomic make-up of pollen loads between consecutive foraging trips. This result did not support the predicted relationship between the load gain rate and major-switching.
日本昆虫学会の論文
2000-03-25