Scientists Strapped QR Codes Onto Thousands of Bees to Learn How Far They Actually Fly

We say that hard workers are “busy as bees,” but in a recent study, honey bees felt more like office building employees.

Entomologists and engineers in the US have glued tiny QR codes to the backs of thousands of honey bees in rural areas of Pennsylvania and New York. An unprecedented application of this technology, as a detail paper Published in the journal Nov HardwareXIt will help scientists and beekeepers study how far insects travel to collect food. Excitingly, the experiment has already shed new light on the mysterious behavior of this important pollinator.

Previous studies have shown that bees can forage up to 6.2 miles (10 kilometers) from their hive, but entomologists estimate that this rarely happens. “The goal is to understand whether the 10-kilometer estimate is biologically correct. Can we determine how far honey bees travel from their hives?” Margarita López-Uribe, an entomologist at Pennsylvania State University (Penn State) and co-author of the study, said in a university statement.

QR codes, called fiduciary tags, basically work like badges in office buildings. The team developed an automated imaging system with a sensor at the entrance to the hive to detect each time a tagged bee enters or leaves, allowing entomologists to track their individual foraging times. The sensor records the bee’s individual identity, date, time, temperature and whether the bee is entering or exiting.

Traditional entomology field work is generally less hands-on, but this approach is providing unprecedented insight into honey bee behavior.

“This technology is opening up opportunities for biologists to study systems in ways that weren’t possible before, especially in organic beekeeping,” López-Uribe said. Organic beekeeping involves, among other things, maintaining sufficient space from industrial areas to prevent bees from collecting pollen in contaminated areas. However, because common bee foraging distances remain elusive, USDA recommendations for organic certification may be inaccurate in this regard.

“In field biology, we usually see things with our eyes, but the observations we can make as humans can never measure up to what a machine can do,” he added. In total, the team tagged more than 32,000 bees across six apiaries with QR codes smaller than a human pinky fingernail that do not harm the bees or hinder their movement.

“We targeted young bees so we could more accurately track their age, specifically when they start flying and when they stop,” said Penn State’s Robin Underwood, who participated in the study. Young individuals are easier to handle because they do not sting yet.

So, what are the bees doing?

The researchers found that most trips to the hive typically lasted between one and four minutes—perhaps potty breaks or quick weather checks—and some longer trips were still less than 20 minutes. However, 34% of tagged bees were out of the hive for more than two hours.

This long absence may be due to long periods of grazing. Some longer trips, for example, corresponded to periods of low flowering, during which bees had to travel further to collect their dues. However, the scientists also acknowledge that the data may be skewed by bees that simply do not return to or enter the hive, effectively hiding the QR code from the sensor.

Additionally, “we also found that bees are foraging much longer in their lifetime than initially thought,” Underwood said. Entomologists previously suggested that honey bees live about 28 days, he explained. However, “we’re seeing bees foraging for six weeks, and they don’t start foraging until they’re already about two weeks old, so they live a lot longer than we thought.”

When they start foraging, bees in the same hive share information about food sources with each other through a so-called “waggle dance.” Now, the team is working with researchers at Virginia Tech to align their foraging data with this behavior to continue investigating how far bees travel from their hives.

Maybe the next step would be to glue little airtags to their backs.