How cool would it be to follow a bumblebee for a day or two? To see where is flies, to see what it does in the nest…
Turns out scientists are beginning to do just that, thanks to advances in technology!
I stumbled across a paper that reports how a group of scientists attached tiny radar tracking devices to four bumblebees, and then followed them for their whole life! Here is a picture of what the radar tracking device looked like:
The device was a small metal pole about 16 mm in length, sticking straight up from where it had been superglued to a plastic disc that had been glued to the bee’s thorax. Apparently these transponders attached to the bees weighed about 15 mg.
Is this heavy for the bee?
To put it into perspective, worker bumblebees weigh between 175-200 mg, so the transponder is only 8-10% of the bee’s mass. As the authors of the study point out, worker bumblebees can carry pollen loads of up to 90% of their body mass. So the transponder is small potatoes to the bee!
The bumblebee nests were beside a large field of mostly thistles. The researchers tracked the four bumblebees until death or until they did not return to the nest for 48 hours, by which time they were presumed dead.
What did they find?
Here is a handy-dandy table that summarizes the “lives” of the four bumblebees:
Note: Exploitation flights were flights that were a single loop, with a stop where the bee had stopped in the past. Since bumblebees tend to return to flowers from which they gathered nectar and pollen, exploitation flights were assumed to be trips where the bees collected food. All other flights were categorized as exploration.
Four (out of many) Things to Notice from the Table Above:
- There is so much variability between the four bumblebees! Bumblebees are not just little clones when it comes to their flight and foraging behaviour. They don’t all do the same thing when they fly out of the nest.
- There were occasions when Bees 1, 2, and 3 did not return to the nest in the evening, but returned the next morning. What did they do all night?! They likely found a nice place to hide, as bees can’t fly in the dark.
- Bee 1 was a little superstar: She had way more exploitation flights and more flights in general. She also had the least number of exploration flights before exploitation flights. I wonder why the other bumblebees were not as diligent?
- Poor Bee 2. She lived for only 6 days.
With such differences across bumblebees, can I dare say bumblebees might have different personalities? After all, there’s some evidence that they might have emotions.
Woodgate, J. L., Makinson, J. C., Lim, K. S., Reynolds, A. M., & Chittka, L. (2016). Life-long radar tracking of bumblebees. PLoS ONE, http://dx.doi.org/10.1371/journal.pone.0160333.