In the northeast, the pillbug is not generally something worth glancing at twice. You’ll often find them squirming for cover when you lift up an old pile of logs, or mulch, or dig around in some wood chips. They look ancient, reminding me of the fossilized remains of the Paleozoic trilobites, and where there is one, there will often be many. Like hedgehogs, they curl up into a defensive ball at the first sign of danger (a behavior which is called conglobation), and blend in well with the shadows by sporting sooty armor.
I am northwesterly now, settling into life in the delightful coastal town of Bellingham, Washington. Good food, like-minded and welcoming folks, and a lot of nearby wilderness make this town seem pretty great. My first western pillbug experience, however, came as a bit of a surprise to me. It looked like this:
It was definitely the prettiest pillbug I’d ever seen; a glorious, regal purplish-blue. This archaic-looking armored crustacean was gussied up in a color I’d expect to see near the end of a tropical sunset, not under a rock.
I thought it must be a regional thing. After all, the west coast often does things bigger and better than the east: the breathtaking peaks of the Rockies versus the rolling hills of the Appalachians, our native porcini mushrooms (Boletus edulis group), with a cap the size of an apple, versus the west coast edulis, with a cap that is sometimes the size of a soccer ball. I even asked around, and yes, west coasters couldn’t understand why I was getting so excited about a common purple creepy-crawly.
In spite of all this, I did a little digging in order to definitively lay the whole thing to rest, and perhaps give a name to my lovely lavender isopod. What I found out was both really interesting, and a little bit tragic. Plum pillbugs are not a glorious west coast variant; rather, they are the standard gray variety infected with a virus that turns them violet. The tragic bit is that it is indicative of an early demise; a periwinkle rolly polly likely only has a few days left to live.
The virus is called isopod iridescent virus (IIV) and was first isolated in California in both the Common Pillbug (Armadillidium vulgare) and the Rough Woodlouse (Porcellio scaber). The color change occurs when the virus forms crystalline structures in infected areas, which affect the angle of light refracted off their exoskeleton.
Seems a bit counterintuitive to create something so beautiful right before snuffing it out.
I was digging my hands into a neighbor’s garden bed yesterday, pulling out the long, stringy runners of the quackgrass (Elytrigia repens) so that they wouldn’t resurface as quickly, and found tumbling through my fingers five or six symmetrical circles: tiny, balled-up, timid pillbugs. Though plentiful, and barely distinguishable in hue from the loam I just pulled them from, I found myself endeared, and gladdened by their sickly-seeming pallor, and the fine veins of lighter gray scrawled across their backs, indicative, I’m sure, of a particular species that I don’t know how to name.