GREEN ISSUE: How a strange obsession blossomed into a crucial environmental issue
GREEN ISSUE On a rainy afternoon in April, I'm standing on an abandoned military base on Alameda Island counting bees on a wild rosemary bush. In the three minutes I've been standing here, I've spotted five large, furry bumblebees, flitting from flower to flower, performing the function that keeps the whole ecosystem buzzing.
But the honeybees I often see here are absent. I'm not surprised. As I learned from Bernd Heinrich's Bumblebee Economics (Harvard University Press, 1979) bumblebees are tundra-adapted insects that are better able to forage at low temperatures than sun-loving Italian honeybees.
I've been obsessed with bees for years. My sister says it began when I got stung on the bum as a toddler. My daughter says it started the day we rescued a swarm of half-drowned honeybees that had gotten stranded in high winds on a beach in Santa Cruz. All I know is that my bee obsession really bloomed when we lived on a lavender farm on the north coast of California and I found bumblebees asleep on the lavender, at night.
A beekeeper on the farm explained that, unlike honeybees, bumblebees don't form permanent colonies. Instead, they nest in empty mouse holes and form small social groups that die out each fall. The bees sleeping on the flowers were probably male, he added; they tend to be lazier, while the females do most of the work.
He told me that only the young pregnant bumblebee queens hibernate in the fall, emerging alone the next spring to start new colonies. There are more than 4,000 species of native bees in North America. Some are the size of ants; others are territorial and drive other bees off the flowers they guard. Most are solitary, nonaggressive loners, and some aren't that busy at all.
Curious, I bought a book about beekeeping from a clerk who told me his father once kept bees in Oakland. "Urban honey is the best," he said, explaining that urban gardens often contain unusual and diverse collections of plants. "City bees have far more exotic choices of nectar."
Fast-forward to the present and it seems that the general public also has taken a much more active interest in bees, particularly since 2006 when colony collapse disorder decimated honeybee populations, triggering warnings of a coming agricultural crisis and potential devastation to the ecosystem.
Scientists estimate that bees pollinate nearly three-fourths of the world's flowering plants. These plants provide food and shelter for many species of animals. A 2008 survey by the U.S. Department of Agriculture shows that 36 percent of the 2.4 million hives in the U.S. have been lost to colony collapse disorder, which translates into billions of honeybees.
Some species of bumblebees also are vanishing. Robbin Thorp, professor emeritus of entomology at UC Davis, blames their disappearance on commercially reared bumblebees that are imported to pollinate hothouse tomatoes and then escape into the wild, where they leave pathogens on flowers (see "Buzz Kill," 01/27/10).
But amid such big news, I'm still keeping a diary of notes on bees and focusing on my own backyard on Alameda Island, wondering how I can attract more bees. Xerces Society for Invertebrate Conservation heeded Thorp's thesis and petitioned to stop the cross-country movement of bumblebees, but the Portland, Ore.,-based group has also produced handy pocket guides to help people like me identify bumblebees in the field.
So far I haven't spotted the missing Western bumblebee, Bombus occidentalis. But I did see a bumblebee queen spiraling through a Potrero Hill garden on a mild day in early January. Reached by phone, Heinrich, professor emeritus of the biology department of the University of Vermont, told me that the queen would retreat into her underground hole when the weather got cold and wet again, which it soon did.