Mystery bugs all over Berkeley had people throughout the community wondering about their appearance Friday. Photo: Micah Daigle

Friday afternoon, a handful of readers got in touch with Berkeleyside to ask if we knew the origin of a rash of insects swarming throughout the city.

“What’s up with the clouds of gnat-like tiny flying bugs on MLK around Vine?” asked Susan Macke on the Berkeleyside Facebook page.

Several others got in touch on Twitter.

Via Michael Fitzhugh: “What’s up with the swarming bugs everywhere in the city today?”

Katherine Baylor wanted to know: “What do your sources say about the massive invasion of tiny flies (gray w/ white fuzz) in Berkeley this afternoon?”

Late in the afternoon, we checked with the city to see if there had been any reports, but came up empty-handed. As the weekend was upon us, we figured we’d have to wait until Monday to investigate further.

Shortly after 6 p.m., Nathanael Johnson took a photo (pictured below) and wondered: “What’s the deal with all these little blue flies?”

Photo: Nathanael Johnson

We posted his photo on the Berkeleyside Facebook page half an hour ago, and asked if anyone knew what might have caused the infestation.

Within minutes, we had a reply from reader Christina Tarr: “A friend of mine (Michael Sholinbeck) says, ‘I emailed an entomologist at UCB who told me this: “I had to go out and have a look for myself. They are Adelgids (close relative to Aphids). Probably Adelges cooleyi, the spruce gall adelgid. They are pests of conifers, particularly spruce and douglas fir. These are probably all males flying right now looking for the flightless females. The white color is actual a bit of wax that the insects produce from their cuticle. I have not noticed ‘swarming’ of this species in the Bay Area before. I am not sure what it means other than it was a beautiful day for flying today.'”

We can try to confirm this ourselves early next week, but for now we thought we’d share what we were able to find. Anyone else have any ideas or context? Let us know in the comments.

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Emilie Raguso (former senior editor, news) joined Berkeleyside in 2012 and covered politics, public safety and development until her departure in 2022. In 2017, Emilie was named Journalist...