The U.S. Fish and Wildlife Service will soon decide whether to add several bumblebees to the federal endangered species list. Among them is the western bumblebee — Bombus occidentalis — a species that, if listed, could become a charismatic spokesbee across its range.
Once ubiquitous from New Mexico to Alaska, western bumblebees are now confined mostly to pockets of the alpine Northwest. Their rapid decline since the ’90s is attributed to habitat loss, climate change and a pathogen spread by commercial bees. Without bumbles like westerns, whole ecosystems might falter: They’re among the most important pollinators on Earth.
Yet, aside from the monarch butterfly, insects rarely receive protections. Despite precipitous declines worldwide, they comprise just 7% of federally listed animal and plant species. Many states don’t even count bugs as wildlife. Listings can be controversial, and the western is no exception: Protecting it could reshape rules for using tools like herbicides and prescribed fire. It could also give a face and a lifeline to myriad other creatures.
Where they remain, western bumblebees — or females, at least — are easy to identify: They’re the only bumble in the West with a distinctively fuzzy white rump. Males and females both forage, but only females collect pollen, packing it onto heavier and heavier saddlebags, called corbiculae, before bee-lining back to the nest.
Crossing miles of terrain from their nests, western bumblebees forage from early spring through fall. In the Western Cascades, the year’s first huckleberry blossoms give way to mounds of pink spirea and lousewort, spindly Cascade aster, then late-season goldenrod.
Insects rarely receive protections and comprise just 7% of federally listed animal and plant species.
Climate change is shifting the life-cycle timing of bugs and blooms. That may threaten westerns’ food sources during a crucial seasonal bottleneck: Bumblebee colonies survive just one season; by winter, the only bees still breathing are next year’s queens, called gynes. The earliest and latest-blooming plants may be especially important for sustenance through those shoulder seasons. After all, a gyne’s got to eat.
Another bumble’s future is tethered to the western’s: a social parasite called Suckley’s cuckoo bumblebee that commandeers western nests, workers and food stores to raise its own young. Fast losing its primary host, the western — the last confirmed sighting was in 2017 — it is also up for listing. This decision may be less controversial: Because far fewer remain, it will have less impact on human land use.
Bumblebees are essential pollinators. They fly in colder temperatures than butterflies or honeybees and buzz when they pollinate, releasing more pollen. Some plants even require this vibration, including several agricultural crops, such as tomatoes. That’s why commercial bumblebees (usually B. impatiens) are widely used in greenhouses, where they’ve harbored a deadly fungal pathogen, Nosema bombi — the prime suspect in the decline of numerous wild bumble species, including the western.
Countless other species, big and small, might benefit from protecting westerns. Other pollinators, like butterflies, would get a boost from policies that aim for more blooms and fewer chemicals. Birds that eat bees and bugs — like the olive-sided flycatcher, another Northwest conservation priority — might have more food. Even mammals like bears, which need berries that require early-season pollination, might gain. Outside their habitat, they’d be influencers of another sort: They’re cute, relatable and easily identifiable — ideal tools for garnering human attention and care.
Like most bumblebees, westerns usually nest underground, often in cavities left by rodents like the golden-mantled ground squirrel. Gynes follow sometimes meters-long tunnels underground, where they build a waxy clump of pots to hold pollen and eggs. Scientists believe that threats in and around nests — Nosema, non-native parasites, human activity and others — may be a greater danger than foraging habitat loss. Few nests have ever been found, but westerns seem to prefer sites tucked along forest edges, often near early-blooming huckleberries.
Illustrations by Ricardo Macía Lalinde/High Country News
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This article appeared in the September 2024 print edition of the magazine with the headline “Get to know the western bumblebee.”
