But I can’t purchase a bumblebee hive! There are none for sale.
Therefore, beginning with the back yard that I can control, I need to make my neighborhood a more welcoming habitat for bumblebees. I suspect that much of what I accomplish, will have positive spillover effects to other native bees and pollinators.
Bees evolved from wasps. Both wasps and bees consume nectar. However, wasps are carnivores, dining readily on other insects. Bees are the Vegans. Bee food consists solely of flower nectar (carbohydrates) and flowering plant pollen (protein). From these two things, they feed themselves and create honey to store for the time when pollen and nectar are no longer available seasonally.
There are an estimated 4,000 different varieties of Bees in the US. The amount of pollinators in your garden is a function of the local ecosystem. The local ecosystem is what you and your neighbors live within and can have a role in shaping. It has been well established that pollinator diversity is beneficial in terms of pollinator efficiency. Measurements of organically managed habitats usually find greater than 10 different pollinators varieties, not all of which are bees.
Honeybees gathering nectar and pollen can range as far as 3 miles from the hive in search of food. Most bees are thought to travel far less. A bumblebee’s range is estimated to be on the order of 1/2 mile, being somewhat more limited by their inefficient aerodynamics. If you presume the normal range is half the extreme, then most of a bumblebees food is within 1/4 mile of it’s nest. It is not thought that most other bees travel as far as bumblebees. This means that you can reasonably expect the Bumblebee and other bees that pollinates your vegetables to nest and over-winter in your immediate neighborhood.
In making my local environment attractive for all bees, the attraction will also extend to other beneficial insects. Expect to find beneficial parasitic wasps and beetles as well as moths and birds in an organic pollinator friendly habitat. In this note, we’re only about bees, but the benefits are great so pursue the topic far beyond this note.
Habitat for bumblebees consists of 3 separate items:
- Food for the bumblebees
- A nesting location
- An over-wintering spot
I need to establish that even with a honeybee hive nearby, other pollinators are able to remain in my garden/ yard/ neigborhood. The strategy for accomplishing this sounds deceptively simple:
- Create places in my yard where bumblebees are likely to hibernate/overwinter.
- Create places in my yard where bumblebees are likely to make a summer nest.
- Plant nectar and pollen producing native plants in my yard that bumblebees are known to favor.
I soon discovered that only one of these three items is well understood: the native plants bumblebees favor. One approach would be to make certain that more of the plants that only bumblebees can pollinate are in my neighborhood, therefore, I will plant enough tomatoes to make tomato sauce. That would be a win-win!
I began this note thinking that the food sources were the most important. I now believe that food sources are the easier to control over the long-term, as we still don’t have a lot of ready answers about nesting and overwintering.
Update 2017: There are commercial bumblebee growers that sell their hives/colonies to large commercial greenhouse growers, so there is more to learn here.