Tiny QR codes help scientists track bee movements

Most bees leave their hive for only a few minutes at a time, researchers found. (Penn State via CNN Newsource)

New insights into bee movements and life cycles have been uncovered after researchers tracked the insects using tiny QR codes glued onto their backs.

By recording when bees entered and exited their hives, scientists from Penn State University (PSU) discovered that, while most journeys last only a few minutes, a minority of bees can spend up to two hours outside the hive foraging for food, according to a statement from the university last week.

“This suggests that most of the foraging that the bees do occurs very close to the hive,” study co-author Margarita López-Uribe, an associate professor of entomology at PSU, told CNN on Monday.

As well as foraging, bees who go on longer journeys may simply be exploring, while others may never return to the colony, said López-Uribe.

Bees are commonly believed to live for around 28 days, explained Robyn Underwood, Penn State Extension educator in apiculture and co-author on the paper. However, the data suggests that bees have longer lives than previously thought.

“We’re seeing bees foraging for six weeks, and they don’t start foraging until they are already about two weeks old, so they live a lot longer than we thought,” said Underwood in the statement.

The team, made up of entomologists and electrical engineers, attached AprilTags, a kind of QR code that is smaller than the nail on your little finger, to the bees using glue.

López-Uribe said this “took a lot of practice” to get right.

“If you don’t add enough the bees can remove the tag, but if you add too much you can get glue all over the bees’ bodies,” she said.

They then used an automated imaging system to monitor bees’ movements through a customized hive entrance 24 hours a day, seven days a week, and the use of affordable equipment allowed the team to track more than 32,000 bees.

This method expands on conventional entomological field work practices, which rely on human observations over limited periods, said researchers, who hope that their method will be used by other entomologists.

“One of the goals of developing this system open-access and with low-cost equipment was to be able to transfer this method to be replicated across dozens (or hundreds) of landscapes,” said López-Uribe.

Researchers are aiming to work out how far bees will fly from the hive to forage for food, if there are enough food sources nearby.

“The underlying assumption of the study is that if hives are placed in areas with enough high-quality food, they will tend to forage close to the colonies, meaning that beekeepers could ‘limit’ the foraging area of bees,” said López-Uribe.

The ultimate aim is to use this data to bring strengthen organic beekeeping standards in the United States.

Current standards stipulate that colonies must be placed in areas that are pesticide-free within a 5-kilometer (3.1-mile) radius, she added.

The paper was published in the journal HardwareX.