I had the pleasure of witnessing this show of defensive warfare at a friend’s house two weeks ago! A friend of mine called me wondering whether this group of bees would be a worry to her children, so I went to check it out.
When I showed up it appeared to be a display of defensive parameters, as six bees were stationed between 13-16 paces from a giant tree with one on the tree, which sat at the center of this circular front. I tested this parameter preference by removing a play structure one bee had been stationed on for quite some time, and replaced it with a chair. The bee finally returned to the same position, perching itself on the chair! And before I placed the chair she was perched on a small flowering plant, which was also the same distance from the center! Pretty fascinating that they were all fixed at equal distances from the center; just another mathematical habit bees have. And we thought humans were the only ones capable of mathematical tactics!
Bumble bees do this because they have something to protect, a queen and a small hive, including between 50-200 bees in the colony. They all work together to provide for the queen and the brood (developing young). This instance shows signs of the nest being inside the tree or underground below the tree. I searched for signs, but wasn’t able to locate the nest, but all signs pointed to the tree.
I watched this situation for a while and noticed these bees would all go after another flying intruder every so often, which appeared to be another bee. They wouldn’t allow that bee near the tree. They were all on high alert, but my presence didn’t seem to bother them, even when I was standing right next to the tree. The trouble was the other bee, which I wasn’t able to identify and capture with my camera.
This species of bumble bee is Bombus Griseocollis, and has an orange belt at the top of the abdomen. They are rather large, but not aggressive toward people, just territorial toward other bees and potential honey and brood robbers (skunks, badgers, etc). They don’t seek out warfare, but rather form defensive tactics.
If you see this in your own yard, consider yourself lucky and enjoy the free show provided by nature. They won’t hurt you, please let them nest and feed in your yard, as their environmental choices are shrinking as we develop more and more. Create a complete habitat for them by planting a host of flowers and place a watering hole for them too! Do not spray them with pesticides! We need our bees!