Bees, beetles part of my prickly search among anthills

Strange things happen out on the Old Spanish Trail at the Whitewater trail head. There are several species of ants out there. I don't know how many, or the names of the different types. But just visibly, there are several species: the little ones, the red ones and the black ones. I know, that's not very "biological." My wife was very disappointed in me.

But here is what's interesting. All the ant hills are very much alike. Some, of course, are obviously newly established and small. Some are dead and no longer inhabited for whatever reason.

But healthy, vibrant ant hills all have this clearing around them that is stripped of all vegetation. You've probably seen them.

On the average, all the clearings have a radius of about 1.4 meters. I measured a bunch of each ant-type hills with my walking stick and then came home and converted "walking-stick" units to meters.

Each ant hill denudes about 6 square meters of soil. The dead ant hills averaged about the same, like maybe that was a limit on the space they take over.

However, there is one plant that seems to grow in the denuded area where nothing else does: sego lilies. It's not that they grow there selectively. They grow other places too, in even greater abundance.

But many ant hills have sego lilies growing within the denuded area, and the ants just ignore them. Why is that?

And while I am at it, what pollinates sego lilies? There has been a great crop of them this spring because of the moisture.

I am especially interested in native bees, and so I check all flowers carefully for pollinators. I haven't seen a single insect on a sego lily.

Desperate for information, I even Googled for pollinators of the sego lily. One reference said it was insects.

Yeah, well, there are about a million of those, so that isn't too specific. I'm guessing it could be moths, since I have only checked during the day, and moths are mostly active at night.

Speaking of pollinators, one of the reasons I have been hiking the Old Spanish Trail is to look for native bees as well as cactus.

For the past couple of years, I have been on a self-imposed research project to learn about native prickly pear cactus. Last year was so dry that it was a waste of time because almost none of the cactus flowered.

This year, the cactus is blooming, and I had a theory that native bees would be important pollinators of opuntia (prickly pear).

The reason, I thought, is that native bees have a peculiar life cycle that makes them well-adapted to desert environments.

Well, the opuntia just started blooming in the final days of May. There are two species of opuntia on the Old Spanish Trail and at first, they all bloomed a hot pink.

However, around June 6, some yellow blooms began to appear. Some of the yellow blooms appear to be on the same plants as the pink ones. But opuntia forms hybrids a lot, and it isn't always clear if two species might not be growing intermixed.

But here's the thing. I have only seen two native bees in a cactus flower, and they were both in yellow blooms situated closely to pink blooms. I have seen no bees in pink blooms.

The literature claims that opuntia is pollinated by beetles, and I have seen a lot of them in the flowers. But they don't seem to gather much pollen on their bodies.

I know, scientists like to tell you everything they know. I am not saying no one knows the answers to these odd observations.

But, if you are an amateur naturalist, you might like to know that western Colorado is great country for indulging your curiosity and increasing your knowledge.

Naturalist studies seems to be a greatly neglected, outdoor-recreational activity in western Colorado.

Gary McCallister, gmccallister@bresnan.net, is a professor emeritus of biological sciences at Colorado Mesa University.

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