Insect Picture of the Day

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Reader Mark White sent in this great photo of a dragonfly he stalked at his daughter’s soccer game. He doesn’t know much about it, and sadly neither do I. I suspect it’s a skimmer, but that’s about like identifying a man by saying “I suspect he was right-handed.”

When I identify a bug, I often start with coloration, and this is why I am so obviously inexpert. Coloration is often meaningless for identifying species–for example, what color is Homo sapiens? Identifying dragonflies is a very complicated affair, but fortunately it is indeed largely based on coloration. Unfortunately, it is a very complicated affair. You and I look at that picture and see a yellow dragonfly with brown spots on its wings. A biologist needs to know a lot more: what color is the face? eyes? thorax? wings? And not just the coloration, but the pattern as well. Oh, and not just the wing, but the parts of the wing: what color is the pterostigma?

(Umm… yeah. I had to look it up, too. It’s the tiny bit on the front edge of the wing almost at the tip. In this photo it is reflecting light and almost looks pink.)

Anyway, once you know what all those colors mean, you can identify your dragonfly. Oh, but wait. According to bugguide, dragonflies can change color: right after emerging, they are sometimes nearly colorless and change coloration several times over the first few days. Some change color when they die. Still others change color with temperature (insert novelty coffee-mug slogan joke here).

So yeah. It’s mainly based on coloration, but that doesn’t mean it’s simple. As far as I can tell, it’s a yellow dragonfly with brown spots on its wings.