QR CODES ON BUMBLEBEES by Mia Hanson

This article originally appeared in the Summer 2026 Napa Valley Chapter CNPS newsletter.

For the last two months, I have been capturing bumblebees and putting QR codes on them for a population research study. Every capture starts the same way: I get eyes (or ears; the sound of the bumblebees doing their buzz pollination typically gives them away!) on the bee, I quickly sweep the net, and then maneuver the bee into a vial – their home for the next couple of hours.

An ice chest is used to chill them out for at least an hour. Once they’re adequately sleepy from the cold, they each get outfitted with a unique code that gets glued onto their thorax right between their wings. This allows us to identify this specific bee for the rest of the season.

After their nap, we place them on a tray with some flowers to help them get their energy up. And when they’re ready, they fly off. The whole process is non-lethal, leaving the bees to forage, mate, or return to their colonies.

The marked bees can then be “recaptured” on film by dozens of cameras that have been set up around the area. Each camera trap is built to lure in the bees with a bright blue vane trap and a landing platform with a fluorescent bullseye pattern that mimics naturally occurring flower patterns. The camera is mounted on top of this platform and has been programmed with machine learning to identify and only take pictures of objects that look like insects.

This is a mark recapture study for bumblebees to estimate their populations, specifically the Bombus occidentalis or Western Bumblebee that historically had a large range across the Western U.S. and Canada, but has been decreasing since the 1990s. But knowing that every bee we mark could help us facilitate their conservation makes me hopeful for the future of these important critters.