Here in Idaho I typically see large female queens flying about my spring flowers in bloom, but this year I haven’t seen a single overwintering queen flitting about gathering pollen to start her brood nest for this coming summer. There is more and more concern about the dwindling numbers of Bumble species and the following information talks about what we can do to aid in their survival. First, a brief description about their biology and habits taken from my web site www.pollination.com.

Bumble Bees (Genus Bombus) are semi-social bees with some similarities to the honeybee. Bumble bees have a queen that produces drones, workers and other queens. However, the colonies are annual, unlike the honeybee’s year-round colonies. Queens emerge from their winter nesting stage, called diapause, each spring and begin foraging for nectar and pollen. Bumble bees hold pollen on their hind legs like the honeybee. The queen uses the collected pollen and nectar to rear workers.

Bumble Bees

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Worker bees are non-reproductive females. Once the new workers begin to forage, the queen stops foraging and stays in the nest to produce more brood. The workers feed and care for the developing brood. During this period of time, when workers care for larvae and a division of labor exists, the colonies are considered “social”. Towards the end of summer colony begins to produce reproductive queens and drones. When these reproductives mature, they leave the colony and mate. The new queens then find suitable overwintering site and go into diapause over the winter.

Bumble bees form their colonies in existing cavities. Depending on the species, they may inhabit abandoned rodent nests or cavities in logs. There are about 30 species in North America, and at least two have been domesticated for use in agriculture. New technological developments have made colonies available on a year-round basis. In western North America, Bombus occidentalis is the native bee that is available as a pollinator. In the east, Bombus impatiens is available as a pollinator. Bumble bees are currently used commercially for pollination of greenhouse tomatoes and peppers.

The bumble bee is an excellent pollinator in a greenhouse environment. The colonies are housed in a box with a small opening which allows the bees to enter and exit. Colonies consist of 100-200 workers and a queen. In tomatoes, it is possible to achieve nearly 100% pollinated flowers with bumble bees. Research has shown that bumble bees are also effective pollinators of orchard crops such as almonds, apples and cherries. Bumble bees do not produce harvestable quantities of honey, but they do store a small amount to sustain themselves for short periods of environmental adversity.

Helping Bumble Bees at Home
By Laura Tangley, National Wildlife Magazine, 4/26/2014

Helping Bumble Bees at Home
The good news is that all of us—particularly wildlife gardeners—can help bumble bees in and around our own homes. Here are some of the most important steps you can take:

  • Provide pollen and nectar for food
    • Active from early spring through late fall, bumble bees need access to a variety of nectar- and pollen-producing flowers so food will be available throughout all stages of the insects’ life cycle. Native plants are best because they have coevolved with indigenous bumble bees.
  • Ensure bumble bees have nesting sites
    • Most bumble bees nest underground in holes made by larger animals, while others nest above ground in abandoned bird nests, grass tussocks or cavities such as hollow logs or spaces beneath rocks. In gardens, they may also use compost piles or unoccupied birdhouses.
  • Protect hibernation habitat
    • Because most queens overwinter in small holes on or just below the ground’s surface, avoid raking, tilling or mowing your yard until April or May. If you do need to mow, do so with the mower blade set at the highest safe level.
  • Eliminate pesticides
    • Both insecticides and herbicides should be avoided. In particular, steer clear of systemic pesticides such as neonicotinoids, which are taken up by the vascular systems of plants. This means bees and other pollinators are exposed to the poison long after a product has been applied when they feed on the plants’ nectar and pollen.
  • Help scientists study bumble bees
    • Report the bees you see in your yard or community to Bumble Bee Watch, a new citizen-science project sponsored by the Xerces Society and five North American partners. An excellent guid to the Bumblebees of the Western United States can also be found at www.xerces.org

Save the Date:
Pollinator Week is June 16-22, 2014!

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