July 29, 2003

Excerpted from the Monday, July 28, 2003 edition of the San Francisco Chronicle:

Biologists abuzz over bumblebees' decline
S.F. State student tries to determine what draws species to certain parks

Jane Kay, Chronicle Environment Writer

On a sunny day on Twin Peaks in San Francisco, a big furry black-and- yellow bumblebee was disappearing into bright orange petals of a California poppy plant.

The bee was loading golden grains into her "pollen baskets," hair-lined depressions on each back leg. She was on a mission to find food for her colony.

But she also was performing an important environmental service: spreading pollen from poppy plant to poppy plant, thus ensuring their survival.

Nearby, Quinn McFrederick, a San Francisco State University conservation biology graduate student, was waving a long net over a patch of low-growing wild blackberries. He's the principal investigator on a 1 1/2-year study on bumblebee preferences.

Like other parts of the country, San Francisco is losing its bumblebees. A century ago, San Francisco had nine species of bumblebees. Now scientists can find only four.

Loss of habitat, parasites and pesticides may be playing roles in the decline. In England, studies show that two dozen species of once common bumblebees have disappeared because of the elimination of hedgerows and other land changes. But because of a shortage of data, researchers can't say for certain what is causing the decline in the United States.

Specifically, McFrederick's study is trying to figure out what makes some parks more attractive to bumblebees than other parks. Is it the flowers? Do the bees choose parks for the abandoned rodent burrows favored as nesting sites? Do they prefer parks surrounded by open space or urban buildup?

Read the full San Francisco Chronicle story.

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Last modified July 29, 2003, by the Office of Public Affairs