The Backyard Arthropod Project

Sam found this one under her crib on May 27. It’s a rather striking gold-colored beetle with intricate tracery on the wing covers.

This is certainly one of the Calligrapha leaf beetles[1]. Based on the dark green pronotum (the plate between the head and the wing covers), it looks like it is related to Calligrapha alni, the Russet Alder Leaf Beetle. I’m not so sure it is that exact species, though. While the pattern on the wing covers is very close, the examples in Bug Guide show more of a rusty coloration, and a bit less gold.

If it is the Russet Alder Leaf Beetle, then it eats (Surprise!) Alders. Most likely, they are eating the shrubby alders that grow around here in boggy areas, and specifically in the boggy area just north of our house. These beetles are not particularly common, and the plant they eat has negligible economic value, so as you might guess, this is not a particularly well-studied beetle.

I’m not seeing any specific description of what their larvae eat, or for that matter a lot of information about them in general[2]. It looks like lot of other leaf beetle larvae eat roots of the host plant, and the adults then come topside to eat the leaves, so there is a good chance that the larva of this one live underground and eat alder roots.

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[1] I expect that they are named this because the patterns on their wing covers look like fancy calligraphy.

[2] If you are a professional entomologist trying to make a living, you have to spend most of your time studying things that someone will pay to know something about. That means that things like crop pests, or insects that prey on crop pests, or insects that have direct economic value (like honeybees or mealworms) get studied a lot; insects that have no particular economic value, but are either visually striking or very common, get studied a bit; and insects that are neither economically significant, common, nor otherwise striking basically barely get studied at all. And even when an entomologist has the wherewithal to study the more obscure bugs just for the sake of it, entomologists are pretty thin on the ground, so they can’t be everywhere and will naturally miss a lot. As a result, entomology is one of those fields where an enthusiastic amateur can actually make a real contribution. The big issue is for all the amateurs to be able to compare notes and compile their information in accessible locations, like BugGuide. Or, for that matter, to publish in journals like The Great Lakes Entomologist. As long as the observations are carefully made and the information is presented clearly, they don’t care whether you are a “professional” entomologist or not.

Other articles related to this topic:

• Net-Winged Beetle
• Three-spotted flea beetle
• Hermit Beetle (and relative)
• Caterpillar hunter beetle
• Red Turpentine Beetle