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Science Snippet: Bumblebees’ Pollen Baskets

 

Competition for pollen often results in two bumblebees crowding into the same partly opened flower, as shown here. Arrows show three of the four expected pollen masses associated with the two bees. The other mass is behind the bee’s bodies. A tiny spider sits on stop of the flower.

Competition for pollen often results in two bumblebees crowding into the same partly opened flower, as shown here. Arrows show three of the four expected pollen masses associated with the two bees. The other mass is behind the bee’s bodies. A tiny spider sits on stop of the flower.

Bumblebees (genus Bombus) carry their shopping baskets on their hind legs. These “pollen baskets” are made up of specialized hairs that quickly sweep pollen from flowers into a mass attached to the leg. The mass continues to grow as the bee moves from one flower to another, where it cozies up to the pollen-bearing parts of the flower (the anthers), and begins vibrating its body so rapidly that the ultrasonic buzz literally shakes the pollen free. Lots of the pollen grains also stick to the surface of these fuzzy bees, but much of it is swept into their pollen baskets. Once the basket is loaded with pollen the bumblebee’s wings, beating at 200 times a second, carry the bee back to the nest where the pollen is unloaded and used to feed larvae. The bumblebee also has a long tongue that it can use to slurp up energy-rich nectar along the way, assuming that the flowers permit entry of the tongue (bumblebee’s tongues vary in length, depending on the species). If you raise tomatoes, you should be especially nice to bumblebees, for they are the champion pollinators of these plants. They also play significant roles in pollinating kiwi fruit, cranberries, blueberries, and strawberries. The next time you hear bumblebees buzzing around your flowers, be thankful. (biobees.co.nz; thebumblebeeproject.weekly.com; xerces.org/pollinator-conservation/native-bees/; other sources)

 

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