In the wake of Colony Collapse Disorder, the European honey bee (Apis mellifera) has become something of a household name, but the diverse array of native bees in North America has received shorter shrift. That’s a pity because most are lovely, charming, beneficial little insects, and none more so than the bumble bee (genus Bombus). The charm of the bumble bee is aptly reflected in the diverse array of common names attached to it, which include dusty miller, droner, humble bee, and, much to the delight of Harry Potter aficionados, dumbledore. Many of these names refer to the noise made by these big fuzzy bees; to “bumble” used to mean to drone or buzz, and the sight of a fluffy bumble bee is invariably accompanied by its loud droning hum. Even those who suffer from melissophobia (the official term for a fear of bees) can relax around bumble bees, as their mild dispositions live up to their teddy bear appearance. Bumble bees are social insects, like their imported honey bee cousins, but their colonies are small (ranging from ~50-800 bees) and only last one year. With no hive full of honey to protect, bumblebees are less territorial and aggressive than honey bees, and I have held many a bumble cupped in my palms with no fear of being stung (which is not to say a sting is impossible, especially if you wander unwittingly too near a colony while mowing the lawn or weed-whacking).
Bumble bees are usually the first bees on the wing in spring and the last ones flying in the fall. Virgin queens mate at the end of summer, then spend the winter in hibernation. That new queen never needs to mate again; she will use the stored sperm to fertilize eggs that hatch into her daughters, and she will also lay some unfertilized eggs that develop into males. These young queens awaken in Spring, their fuzzy black-and-yellow or -orange coats providing insulation that enables them to be active on days that are too cold and damp for honey bees to forage. Once she finds a dry, sheltered cavity to serve as a home for her soon-to-be-growing family, she gets down to the business of provisioning the nest, making small wax pots which she fills with the nectar and pollen she gathers. She lays her first batch of eggs, and uses her own body to keep the temperature warm enough for the developing embryos. She continues her solitary maternal care of this brood, feeding and tending the larvae until they pupate and the first generation of daughters emerges and takes over in caring for subsequent batches of sisters. With just the queen to tend their needs, this first generation is usually smaller in size than their mother, but as the queen continues to lay fertilized eggs, there are more daughters to provide forage for the larvae that develop throughout the summer. This is no small task, as laboratory studies have found that a nest of 100 bumble bees can consume up to 2 g (0.07 oz) of pollen and 40 mL (1.4 oz) of sugar syrup daily! At the end of summer, the old queen lays some eggs that develop into new young queens, as well as some unfertilized eggs that develop into males that quickly fly off to find mates of their own. The old queen dies and the new virgin queens make their mating flights and then hibernate through the winter, to await the following spring.
There are about 40 species of bumble bee in North America, but several have experienced serious declines due to pesticide use, habitat loss, and disease. Supporting your local bees isn’t that hard to do; just plant a patch of organically-maintained habitat that provides bloom from early spring through fall and watch how the bumbles and other native bees respond. And if you would like to contribute data from your own pollinator patch to larger studies on the status of bees in North America, check out the Great Sunflower Project (greatsunflower.org) to get involved in the Great Backyard Bee Count and find field guides (including guides to bumble bees of the eastern and western United States), image galleries, and information about the life history of bumble bees and other native bees.