Bumble Bees of BC

Tricoloured bumble bee (Bombus mixtus) on Blazing Star Flower (Liatris spicata)

Bumble bees belong to the genus Bombus which in Greek means “a buzzing sound” because of the low hum these bees make. There are over 250 species of bumble bees world wide with less than 50 in North America. Bumble bees are medium to large bees that tend to be fuzzy and are among the first out in spring and the last to be seen in the fall. They will bask in the sun to warm up but if that doesn’t work they can uncouple their wings and shiver their flight muscles to warm up.
Bumble bees are eusocial meaning “truly social”. Bumble bees tend to nest underground or on the surface among leaf litter, wood pile, or cavities within rock piles. They will also take advantage of holes in houses, birdhouses or nest boxes built especially for them. The only bumble bees to survive the winter are the queen bees, which will emerge in spring and search for a good nest site. Then, she will go and forage for pollen and nectar to stockpile in the nest, which she will lay her eggs on. She will sit on her eggs similar to a bird sitting on its eggs, and will only leave the nest to collect more pollen and nectar. When the first brood becomes adults in about a month, they will take over the job of foraging for food and help look after the young. The queen continues to lay eggs throughout the summer and near the end of the season she produces male offspring (drones) followed by female offspring that will become the queens for the following year. The males die after mating, and the new queens will find a new place to hibernate for the winter and the cycle will repeat itself the following year. The old queen and workers will die at the end of the season.
Bumble bees are generalist forages and some have long-tongues enabling them to reach nectar in deep throated flowers like honeysuckle and others are medium-tongues. Some flowers need to be buzzed pollinated, such as nightshade family plants which includes tomatoes and this can only be done by bumble bees. Some plants you can use to invite bumble bees to your garden could include: borage, campanula, legume family plants like lupines, chives, crimson clover, lavender, penstemon, self-heal, snapdragon, heather family plants like rhododendron and huckleberries, roses, willows and asters.
Bumble bees are often used in greenhouse operations to pollinate crop plants, such as tomatoes. The Western Bumble bee (Bombus occidentals) was use in greenhouses but has been on a steady decline. It was once abundant in the lower mainland of BC but now is rarely seen. The common eastern bumble bee (Bombus impatiens) is used in greenhouse operations here in BC, and these bumble bees have escaped and are now overtaking many of the native bumble bees, as they are a more aggressive bee.

Common Eastern Bumble Bees (Bombus impatiens) on sedum plant.

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