While the entire state has only 20 or so species of bumble bees, there are 400-500 different species of native wild bees in Wisconsin. 85% of these species are solitary bees. Some are tiny, some are black, some are green. They build their nests in small cavities and cracks or underground, and often emerge the next season. New bees emerge in spring from the eggs laid the previous summer. These solitary bees cannot fly very far, and need about 30 trips to collect the pollen needed for one egg.
We paid attention to bumble bees working up the stalks of wild white indigo. The bumble bee collects pollen by pressing the keel of the flower downward and then rubbing its hind legs on the exposed anthers. As the bumble bee works its way up the plant stalk, the pollen from the male blossoms at the top of the plant is deposited on the bee and then transported to the next white indigo plant it visits.
While Bumble bees often prefer certain flowers, such as columbine or Monarda or white indigo, they develop deft approaches for extracting the nectar from flowers with very different architecture. For example, they will approach a wild columbine by thrusting their head into the spur of the hanging flower. A rusty-patched bumble bee may perforate the top of the spur and reach the nectar the easy way. On an oxeye sunflower bumble bees forage across the flower head to gather pollen from the many tiny flowers when in bloom. On a yellow cone flower, or culver’s root, or catnip they will work their way around the flower cone or stalk, visiting all the tiny blossoms.
Thank you Susan, for teaching us. What a great show and tell session we had in the Preserve. To learn more about bumble bees visit https://beespotter.org/topics/key/