An ecology lesson

Along the path I take to work I observed a strange occurrence over the past several weeks. I first detected clusters of tiny yellow and black striped caterpillars on a few ugly looking weeds, and from there the caterpillars proceeded to grow rapidly, literally stripping the weeds bare, including their flowers and branches. After three weeks the weeds were nothing more than sticks, and most of the caterpillars had disappeared too. I suppose a casual observer would perceive that the mother moth had left her little ones in a precarious position, having been placed in a weed patch with few ready comestibles. Or perhaps the weed these caterpillars fed on was an extremely rare species, and the caterpillars themselves were also of a rare breed of butterfly or moth, and what was being witnessed was another example of the fragility of life on this planet.

And I was, in a fashion. What I was in fact observing was deliberate pest control. The weed in question is the tansy ragwort, an import from Europe. The weed is poisonous, and can be deadly to livestock that eats it when mixed in with other silage. Milk taken from cows that eat the weed can be toxic. The weed is difficult to control long-term, because its seeds can lay dormant for a decade or more. The state of Washington has declared war on the weed, and its weapon is the ragwort’s natural enemy, imported from abroad. Like the Monarch butterfly caterpillar which feeds on the poisonous Milkweed plant, the Cinnabar moth caterpillars have exclusive claim on the ragwort. And they perform their mission admirably well; no ragwort in the vicinity is safe. However, as I observed, few if any of the caterpillars survive to pupate. They are voracious eaters, and when they have stripped the ragwort bare, they proceed to eat each other, and if the few that are left don’t have any cousins to eat before they have completed the larvae cycle, they starve to death.

That is our ecology lesson for the day. Now only if the Democrats could learn how to strip down and expose those Republican weeds down to the barren, lifeless twigs that they are--without, of course, eating each other in the process.