The importance of bumblebees can’t be overstated as pollinators for agriculture both in the field and in greenhouses. Unlike honey bees, they are able to forage under cold, rainy, and cloudy conditions, so it is possible to see them in all kinds of weather. Even in an early cold morning, you can see a bumblebee sleeping inside a flower blossom, waiting for some warmth to arrive. The crops that bumble bees can pollinate include tomatoes, peppers, raspberries, blueberries, chives, cucumbers,apples, strawberries, alfalfa, blackberries, soybeans,sunflowers, beans, cherries, apricots, plums, almonds,nectarines, peaches, rosehips, eggplants, and cranberries.
Bumble bees are also extremely important pollinators of many flowering plants and are generalists, which means they pollinate by visiting hundreds of flowering plants. Their wings beat 130 times or more per second, and the beating combined with their large bodies vibrates flowers until they release pollen, which is called buzz pollination. Buzz pollination helps plants produce more fruit.
Bumble Bee Declines
There is evidence that in North America some of our bumble bee species are declining and a few are
threatened with extinction. Species that seem most vulnerable are those with smaller climate tolerances and those that emerge later. Many species in North America and around the world, are declining at a rapid rate.
Currently, the suspected threats to wild bumble bees are:
1. Habitat loss due to agricultural
2. Urbanization or pollution
3. Pesticide use
4. Pathogen spillover from managed bees
These are the same threats that honeybees face.
Move in Ready
Most bumblebees nest in underground nest, or old logs or crevices. You can help the bumblebees come to your property and nest by providing a ready to move in nest, just as you would to mason bees.
I have mason home plans at Home Sweet Home for Mason Bees.
Since most bumbles nest in the ground or a dry, dark cavity, you can provide a simple ground nest with a clay pot, a saucer, some straw, piece of chicken wire, and a short piece of garden hose for an entrance. The low-flying zig zag flight of a nest-site searching queen can be seen in the spring and is very distinctive.
A mature nest of a bumblebee can contain up to 400 residents, as compared to 50,000 to 80,000 honeybees, so the nest is quite small. It should be located in the shade in a dry location. The straw used preferably should be obtained from a mice nest, as a queen will be attracted to the smell. For complete instructions and diagrams, go to Hartley Botanic. The queen will overwinter in the nest to start a new colony in the spring.