Scientists at Penn State University used an unusual method to track honey bees. By placing tiny QR codes on the backs of the bees, the researchers can keep track of when the bees leave and return to their hives. The work will help scientists learn more about how bees collect food and how far they travel.
Honeybees, Pollen, & Nectar
Honey bees are important pollinators. They travel from flower to flower, collecting pollen and nectar. The nectar is what the bees use to make honey. Bees bring pollen and nectar back to their hives, where they store it and use it to feed the hive’s young bees.
Scientists have long had questions about how far bees travel to collect food. They believe bees can fly as far as 6 miles (10 kilometers) if they need to. But most of the time, bees probably don’t fly so far
(Source: PSU.edu.)
Researchers at Penn State wanted to get a better idea of how far bees usually travel. So they worked with electrical engineers at the university to develop a way to track bees. Bees are usually studied in a lab or near one. But the scientists wanted to develop a system that could work anywhere and be used by just about anyone.
They decided to use simple codes called “AprilTags”, which are similar to QR codes. These codes are easy for cameras to track and decode, even when the lighting isn’t good. They are small (smaller than a fingernail), and can be glued onto the back of a bee without causing any harm.
But gluing on thousands of tags was a lot of work. The researchers focused on young bees, tagging 600 of them every two weeks. Over the spring and summer, the scientists tagged over 32,000 bees spread across six different hives.
(Source: PSU.edu.)
By placing a solar-powered camera and a tiny computer above the entrance to a hive, the researchers could track the movements of the each tagged bee. They could tell when each bee left the hive and when it returned. They could also record the temperature.
The new system gave the researchers a lot of information about the bees’ movements. They found that most trips outside the hive took between one and four minutes. The scientists think these short trips were used for quick jobs like checking the weather or pooping. Most trips, even longer ones, were shorter than 20 minutes.
But about 34% of the bees took trips that lasted longer than two hours. The scientists say this could show that the bees were making longer trips to collect food. The researchers noticed that the bees spent more time out collecting when there were fewer flowers around. But some of these “long trips” could also be mistakes, where the camera didn’t catch the bee returning.
(Source: Penaloza-Aponte et al., [CC BY 4.0], via HardwareX.)
The scientists were surprised by how long the bees lived. Before the study, scientists thought honey bees lived for about 28 days. But the tagged bees didn’t start collecting food until they were roughly two weeks old. And the researchers discovered that the bees continued to collect food for six weeks after that.
Scientists know that bees use a special “waggle dance” to communicate with each other about where to collect food. Now the researchers want to see how their new tracking information matches up with these special movements. They plan to teach beekeepers and other scientists how to use their tracking system.
Did You Know…?
Knowing how far bees travel to collect food will help beekeepers be more careful about what goes into their honey. For “organic” (more natural) honey, for example, it’s important that the bees not get nectar or pollen from plants that have been sprayed with pesticides.