Unlike honeybees, which were brought from Europe during the colonial period, bumblebees are native species to North America. Moreover, different bumblebees are found throughout the Northern Hemisphere, and in South America where some lowland species have been identified. There are forty-six known species endemic to North America north of Mexico, of which nearly 20 species exist on Vancouver Island.
Bumblebees are very effective pollinators, known for their ability to “buzz pollinate” through sonication which is a technique used by many bumblebee species to dislodge pollen tightly held in the anthers of a plant. This is especially beneficial for improved crop fertilization and yields of plants like tomato, blueberry, cranberry, and kiwi. With this, many bumblebee species have developed a foraging niche distinguished by their proboscis (tongue) length; where, species with longer proboscis can reach nectar from tubular with long corollas, while those with short proboscis are most efficient at harvesting nectar from smaller flowers. Also bumblebees can maintain a relatively consistent body temperature by rapidly moving their thoracic flight muscles to generate heat. Therefore, even in cool and wet weather, where other pollinators do not dare to come out, bumblebees are actively out foraging.
Bumblebees are social insects like other species of bees, meaning that related individuals will cooperate to forage for food, rear offspring, and defend their nest. Similar to their close cousin the honeybee, queens, workers, and males perform specific functions within the colony. However, bumblebee colonies do not persist throughout the year. Rather, new bumblebee colonies are established each spring and will climax with the floral resources available. At the end of each growing season, bumblebee colonies will die off, only to start again at the beginning of the following growing season with the founding of a new colony when an overwintered, fertile queen emerges from hibernation in spring to begin anew the process of gathering nectar and pollen for her nest.
Unfortunately, many North American bumblebee populations and their ranges are in sharp decline. The main reasons for large declines are due to habitat loss, widespread pesticide and herbicide use, climate change, and the accidental introduction of bee diseases. Since bumblebees produce smaller annual colonies that have smaller population sizes, they are at high risk of extinction. Many once common bumblebee species are either rarely encountered in the wild or are now extinct.
How to help the Bumblebee?
Bumblebee populations are under pressure, and it requires all of us to do our part to help conserve and re-establish the former range of these important and unique species. The first and most easy step is to eliminate the widespread use of pesticides and herbicides; for they are consistently shown to have detrimental impact on native bees and their habitat.
We can also help promote bumblebee populations by providing them nesting sites in gardens, farms, and high forage areas. Typically, a bumblebee queen will not dig her own nest, but rather occupy abandoned rodent dens, birdhouses, heavily grassed areas, caverns in rock walls, trees, hollow logs, and above ground human-made structures. With this mind home and property owners can do their part by leaving such naturalized structures, vegetation, and areas undisturbed. Moreover, by establishing pollinator gardens and large areas of natural forage, we can help provide much needed habitat and food resources for bumblebee populations.For more information on helping the Bumblebee check out:
Xerces Society - Bumblebee Conservation