Bees are responsible for pollinating plants that provide much of our food; in North America it is believed that 30% of food for human consumption originates from plants pollinated by bees. Honeybees are generally thought of as the most common pollinator, and they are the most widely studied, but bumblebees are the chief pollinators of red clover, alfalfa, and in some areas cotton, raspberries, apple and plum blossom.

In Norwegian orchards honeybee pollination is usually limited by low temperatures, so bumblebees are the chief pollinators there, and in other Scandinavian countries bumblebees will forage 24 hours a day in the long days of summer. Also bumblebees will pollinate flowers that do not produce nectar, whereas honeybees will not. Just look at the photograph on the right. No other animal can pollinate "difficult" flowers like antirrhinum except big, fat, hairy bumblebees. They have to learn how to get at the nectar located at the bottom of the gullet-shaped flower. And even once they know where it is they have to push their way between the petals to get at it. On the way down to the nectar they pollinate the flower and pick up more pollen. This bumblebee is still quite early in her foraging trip as we can see from the small load of pollen she has loaded into her pollen basket.

In New Zealand bumblebees were imported (they have no native bumblebees) to pollinate the forage crop clover (Trifolium pratense) as the corolla is too long for honeybees, so they cannot act as pollinators. Bumblebees are such good pollinators of these crops for three reasons:
1. They can fly at much lower temperatures than honeybees. They can fly at 10^oC and there have been records of bumblebees flying when the temperature was below zero.
2. Many species have longer tongues than honeybees, so they can pollinate flowers with long, narrow corollas.
3. They are very hairy and their hairs are branched and so are perfect for picking up and transferring pollen.

In the 1980s commercial production of bumblebee colonies for glasshouse pollination was started. A honeybee hive would be too large, and also honey bees are unable to perform the "buzz pollination" required by tomatoes. The anthers of tomatoes will only release their pollen when they are vibrated at around 400 Hz. The bumblebees do this by grabbing hold of the anthers and vibrating their flight muscles without moving their wings. Previously an artificial buzzer was carried around by hand to pollinate these plants when they were grown in glass houses. Within 3 years of Bombus terrestris being reared commercially for pollination use in glasshouses 95% of tomatoes grown in Holland had been pollinated by bumblebees. So now almost every European tomato is the result of a vibratory embrace of a bumblebee! Bumblebees are also used to pollinate aubergines and peppers, cabbage and carrot for seeds, kiwi fruits, strawberries, courgettes, aubergines, sweet peppers, cranberries, blueberries and tomatoes for fruit. About a quarter of a million colonies are reared artificially every year (1997), and they are used in over thirty different countries on over twenty-five crops. So bumblebees are of great economic importance, and with the increase of glasshouse cultivation, and the spread of the mite, Varroa jacobsoni and colony collapse disorder, causing a decline in honeybee populations, their importance can only increase.

(C) Copyright 1997-2008