Every now and then I like to turn things upside down in order to see them from a different angle. They say that such a thing actually puts the right side of your brain to work and, incidentally, causes a lot of things to spill (never look at the bottom of a glass when it is half full, for instance).
Nature delights in turning things around as well. I suppose she does this to give us a different view of life and confirm that we should never assume anything when it comes to the natural world. It would be natural to assume that a tiny sand hill with hole in the center is an anthill or that a colorful winged insect flying at mid-day is a butterfly. As a small way of turning your world upside down, allow me to introduce the exceptions to these examples.
First of all, what about those anthills? Yes, some ants do make sand hills. These hill-lets are possessed of a central entrance for ingress and egress, but I digress. Should you come across a sandy spot with a cluster of apparent anthills where the central holes are about ¼ inch wide and open slightly off to the side, you are actually looking at bee hills. If you stick around a minute or two you’ll spot the specific bees belonging to these structures as they return to the surface and poke their heads out. Take a look at the picture above and you’ll see two of these Solitary Bees guarding their burrow entrances.
Solitary bees are members of a group of bees called mining bees (see a close-up here). There are some 1,200 species in North America, so I can’t tell you the exact species of the ones I encountered. These insects produce neither honey nor beeswax. Oddly enough, most wild bees are of solitary persuasion and only a few form genuine colonies such as the caste-forming Honey Bees. This means that, although the honey/wax making species get all the glory, the vast tribes of solitary bees perform a great deal of the pollination work going on out there.
It appears to be another turn-around of ideas to state that these so-called “solitary” bees nest in groups. They do find some comfort being in the company of similar bees, but are not social insects in the true sense of the word. They do not co-operate or assist each other in any way – it’s a “you don’t borrow my tools and I won’t borrow yours” neighborhood thing.
Each one of the separate but equal burrows is independently excavated by a female Solitary Bee. The main tunnel extends down into the sandy soil for a few inches. Brood chambers, or cells, are carved off to the side and at right angles to the main tunnel (here’s a cutaway view of a tunnel with a few side chambers exposed). These chambers are created and waterproofed with a waxy secretion. The female collects pollen (using special brushes called scopae on her hind legs) and rolls it into a ¼ inch ball. A liberal application of nectar provides sufficient moisture to hold it together and provide a bit of sweetener for the kids. She then lays a single egg on the pollen ball (look here – both this and the previous shot were taken by Dennis Briggs of the University of California), and then seals up the chamber for good.
She works on one cell at a time and eventually seals off the whole set after she’s laid eight or so eggs. Her life work is done after several more burrows are completed. Solitary bees do not provide any other parental care other than this initial set-up. The child bees are solo from here on out. They will hatch out later in the summer, eat up their pollen snack, pupate, and await the following spring to emerge as adults. They do all of this on their own. No bee is an island, but these come close.
As if a community of solitary bees living in ant hills isn’t enough, I’d like to add one more contradictory insect to this essay. There is a flashy little moth out there called a Grapevine Epimenis (see here) that flies by day. I encountered several of these on a recent walk and they all were seeking to suck up minerals from the trail limestone.
A majority of moths are night fliers and all butterflies are day fliers. There are some significant exceptions to the moth rule. Some, such as the diminutive Epimenis, find the full light of day to their liking and shun the night. In the field guides, this black, white and red moth is listed as an early spring woodland creature that “is often mistaken for a butterfly.” Trembling with energy, the pictured moth was difficult to approach because it would dart off as if driven by butterfly reflexes. Scientifically this species is called Psychomorpha epimenis which gives a hint at the crazy behavior of this day moth. I prefer to give it the previously unpublished title of “buttermoth.”
If there is any lesson to be drawn from looking at bee hills and pseudo butterflies, it is that few things are as they initially appear.