Those bees make plastic bags!?! I’m going to have to see that for myself!
Have you ever seen something along the side of a quiet country road that made you think, What was that? Then, just because you could, you stopped to investigate?
Well, one April day we were passing a particular roadside bank that had very little vegetation and was speckled with light-colored, leopard spots. So, of course, we stopped to see what those spots were.
They turned out to be little piles of light-colored sand surrounding pencil-sized holes. These holes and sand piles look like miniature versions of old mine entrances (adits) like you see on the mountainsides in the Rockies.
Anyway, as we were observing the holes, there were a lot of bees flying around, and it was obvious that those holes were entrances to their nests. Since this was early spring, only the early flowers like trout lilies, spring beauties, and trilliums were blooming. Oh, and the maples were just starting to blossom.
With a little research, I learned we had discovered a colony of cellophane bees—real bees, not plastic ones. Cellophane bees (Colletes) are solitary, ground-nesting bees that make plastic bags to hold and help protect their nests’ provisions. Of course, I had to dig out a cellophane nest to see one of those plastic bags for myself.
I used my trusty trowel to carefully dig away half of the tunnel as I worked downward. As I cut away the dirt on the side toward the road, I learned to be careful to not let dirt fall into the tunnel, or it would clog it up and I wouldn’t able to follow it.
Soon I was able to cut away the side of one of those bee nests to see a cross section. The shaft went fairly straight down about 8 inches (20 cm) or so and then turned to the right. As I dug, I also encountered some backfilled brood cells. These bees make numerous branches and fill them after the cell is provisioned and an egg is laid in the bag.
The active brood cell I excavated angled off to the right side. At the end of it was a very docile cellophane bee and a plastic bag partially full of a semi-liquid pollen mixture. Some of that pollen likely come from various early spring flowers, but, reportedly, cellophane bees get most of their pollen from blooming maple trees.
Wouldn’t it be amazing to watch a bee manufacturing one of those plastic bags? Now, that would be very difficult, so the next best thing is to see if other people have seen the process. Take a close look at the bee’s brood bag. Do you see what appears to be strands of material on it? Those are silk strands which some researchers recently described as being applied first. In other words, the strands are on the outside of the bag since the bee builds the bag around itself. Next, the bee spreads out layers of the polyester with its mouthparts. This spreading is accomplished using a two-part process. One step is to paint around a secretion from its salivary glands which acts as the catalyst. The second step is to spread out a secretion from its Dufour’s gland which it obtains from its stinger. This Dufour’s gland secretion quickly dries on contact with the catalyst and produces the bag we see.
Think about how amazing it is that the bees seem to do all this without gluing their mouths shut, or getting their wings stuck together, or ending up with their feet stuck on the bag. On top of that, they do this in a tight place! In the dark! Just imagine what a mess I would make, if, while in complete darkness, I tried to glue something with epoxy or super glue. I’d surely end up with glue on my hands, or, worse, my fingers glued together. God gave cellophane bees the ability to make waterproof brood bags, which apparently function to keep moisture both in and out. They also protect the brood’s provisions from fungi.
Plastic bags in bee nests—it was worth stopping to investigate those sand piles, wasn’t it?
