Over the next couple months in Central Oregon, lots of skinny, largely black animals will wake from their long hibernations and come staggering out of their overwintering sites looking desperately for food. Lots and lots of food.
Yes, some of these furry animals will be black bears. But far, far more will be bumblebees. Bumblebee queens, to be exact.
Now, please tell me I’m not the only one who has wondered how this whole thing works—how it is that bumblebees (and other native bees) suddenly appear just as flowers start blooming in spring, then disappear to parts unknown at the end of summer. Where do they go? And how do such small insects survive the winter without the puffy jackets, thick socks, heaters, and hats that we mere humans require?
The Bumblebee Life Cycle
To answer those and other questions, it helps to understand the bumblebee life cycle, beginning with what we’re about to see (and hear) this spring.
As the soil warms up and early flowers start to bloom, bumblebee queens will emerge from abandoned rodent holes, compost heaps, and other hibernation sites. The queens are the only bumblebees that live through winter, so no pressure, but the entire future of each bumblebee species depends on their survival.
To answer the question of how bumblebees survive through winter … well, many don’t. Lots of queens starve, freeze to death, or drown during winter storms. The fortunate ones pick overwintering sites that don’t collapse or get washed away, and they store just enough fat to shiver their way through all those cold days and long nights. In spring, these are the survivors who will crawl out looking for immediate nourishment.
If the queen finds enough nectar-filled flowers to eat and drink her fill, she will soon get to work on the next stage of her life cycle: reproduction. First, she’ll scout out a nesting spot, which might be a hole in the ground or some loose ground under a garden shed. She won’t hang photos on the wall of her new home, but she will tamp it down to suit her taste and fill it with some balls of food (nectar and pollen, held together with wax from her abdomen) to support herself and the young she’s about to raise.
By early summer, the queen will have laid and incubated her first eggs, which will become so-called worker females. These small non-queens will guard the nest, bring back food, and tend to future generations, relieving the queen of some of her responsibilities. In fact, the queen will become a full-time homemaker, never leaving the nest again.
In late summer, the aging, balding queen (I feel her pain) will start producing males and future queens. The males have a straightforward role to play over the course of their brief summer lives: They will leave the nest and look for queens to mate with, although most males will die without succeeding in their singular mission.
The new queens will likewise leave the nest, and will typically mate exactly one time, storing the sperm from that single encounter through the long months of hibernation that lie ahead.
What All This Means
I’ve heard people talk about the need for “all-season blooms” to help native pollinators, but the purpose didn't click for me until I understood the life cycle of the bumblebee.
When those hungry queens emerge over the next couple of months, they’ll need our help. Their lives will depend on finding as many as 6,000 flowers a day on early-blooming plants like Oregon grape and lupines—beautiful plants we can grow in our own backyards. More than that, the bees will need our public lands, where those and many other native plants grow naturally.
Let me repeat: Bumblebees need up to 6,000 spring flowers each day! Think about that, and about all the parking lots and subdivisions and other changes that have removed plants from our world, and you start to understand why six of the 22 bumblebee species in Central Oregon are at risk of extinction. Which, not for nothing, also puts the plants they depend on at risk, because nature is a whole lot more interconnected and complex than a little ol’ blog can capture.
But let’s end on a simple and happy note: Planting a variety of native shrubs and wildflowers that bloom from spring through fall will make our backyards (and alleys and fields and farms) more beautiful and colorful—and more sound-full, when those hungry queens come buzzing back into our lives.