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Survey of California bumble bees fails to detect 8 species historically found in the state

A survey of California bumblebees could not detect a single member of eight different species, historically found in the state. KPBS science and technology reporter Thomas Fudge spoke to researchers who say it’s more evidence that the bee population is declining.

Farming practices and destruction of habitat, along with infectious diseases, have dramatically reduced bee populations worldwide.

Now there is evidence that several species of bumble bees have gone missing in California.

Entomologists from UC Riverside collected 100 bumble bees in 17 parts of the state to examine their biodiversity. Of the 25 species historically found in California, researchers could find no bees from eight of those species.


“I would say one of the most surprising, or alarming things that we found in our study is we failed to find Bombus occidentalis, the western bumble bee,” said Hollis Woodard, an entomologist at UCR. “This is a species we know has declined but we did hope to find it. If I had carried out this exact same study in 1980 I would have found quite a few of them.”

Woodard calls herself a bumble bee researcher, specializing in the big fuzzy bee that people can immediately recognize, and she is senior author of an article in the journal Ecology and Evolution about the survey.

She said the populations of some other species of bumble bees are also dwindling.

“We’re not shocked that we didn’t find them,” she said. “It was further confirmation that these are species that used to be found in California but they’re now exceedingly rare or potentially extinct.”

The list of bees that researchers didn’t find also includes the Crotch bumble bee, the Suckley cuckoo and Franklin’s bumble bee. Those species are important because they, along with the western bumble bee, have just been given protection under state law as endangered species.


Conservationists petitioned to have them listed as endangered. And in a decision that raised many eyebrows, the state’s Third Appellate District Court ruled last month that bees are invertebrates that meet the definition of protected “fish,” under the language of the California Endangered Species Act.

The act defines a fish as “a wild fish, mollusk, crustacean, invertebrate, amphibian, or part, spawn, or ovum of any of those animals.”

California bumble bees are more common in higher elevations and in cooler, milder parts of the state. Woodard said her research team tried collecting bumble bees in parts of Southern California but could not find enough bees to include them in the survey.

Woodard said bumble bees are important pollinators of California crops as well as wild native plants. Bees are crucial to pollinating crops that include almonds, tomatoes and peppers.

She said she hopes protection under the state endangered species act will motivate people to protect them. Given the changes to our environment, she said it’s no surprise bee species have been devastated.

“We have completely changed our landscapes,” she said. “We have transformed how we do agriculture and our pesticide use. We have climate change that has changed the foraging and nesting habitats of bees. So to me, it’s not a surprise that so many bumble bee species seem to be in trouble. To me, some of the bigger mysteries are why some other species have been able to persist and survive in spite of everything we’re doing.”