The other day at Mount Pisgah, I found an insect that I’ll likely never see again. Neither will you. That’s because this individual isn’t colored like the others in its species. I’m calling it the Pink Stink.
This striking character is a true bug in the Pentatomidae, or stink bug, family. The prefix “penta” means five, and refers to the five segments of the antennae. All other true bugs have four. The “stink” part of the common name comes from a defensive odor they emit to scare away predators. I’ve not smelled anything defensive or offensive about these bugs, but I’m told when people squash them, they live up to the name (Hint: don’t squash them!).
It’s likely this is a red-shouldered stink bug, Thyanta custator, or another darn near identical species found only on the west coast, Thyanta pallidovirens. Usually, these bugs are green with red only on the shoulders. Often, there’s a red band across the upper thorax where this one is pink. Because they vary in color, and can sometimes be light brown or tan, I suspect this yellow fellow belongs to one of the Thyanta species.
The coloring makes it easy to see the clear parts of this insect’s wings. The true bug’s order, “Hemiptera,” means “half-wing” because the outer, hardened elytra are partially see-through. There’s another set of clear wings under those as well.
Why is this individual yellow and pink? I have guesses but no answers. Feel free to come up with your own ideas. It could be this is an older individual, and the color has faded. Maybe the raised mark on the right wing is a fungus or parasite that has caused a color change. Or maybe it’s the bug version of albinism.
Although chances are you won’t see this individual insect, you may come across another that has a distinctive and interesting trait, so …
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A PDF guide to some of Oregon’s stink bugs, including pictures of nymphs: https://www.oregon.gov/oda/shared/Documents/Publications/IPPM/StinkBugGuide.pdf
BugGuide’s info page on the Red-shouldered Stink Bug: https://bugguide.net/node/view/15344