Wednesday, May 07, 2014

Speedy woodlouse

A patch of yellow dead nettle is blooming next door, and my neighbour has moved out, so I picked all the flowers to prevent them from going to seed and invading the world. Or at least, my part of the world.

Hidden beneath a flower head, I discovered a sowbug.

Philoscia muscorum, the  Fast woodlouse. Well named.

Moving the stem around to get a better view of him, I knocked him out onto the table, and he took off running, much faster than any sowbug I've seen before. I chased him down, trapped him, and took a batch of photos, then searched BugGuide. He's a European import, and, while he's built like the sowbugs I see every day (aka woodbugs, pill bugs, roly-polies, etc.), he doesn't act at all like one.

First, he runs. Fast. "Our" woodbugs trundle along slowly enough for me to go for a pill bottle and come back, and still find them on their way to shelter.

Second, he "hides" in the first available shadow he finds. He freezes there, and takes quite a bit of nudging before he realizes he can really still be seen. The usual woodbugs here keep on going until they're invisible.

Fast woodlouse "hiding".

Next, if you flip him on his back, he lies there, playing dead. The other woodbugs either roll into a ball (pillbugs, Armadillidium vulgare), or wave their 14 legs frantically in the air until they manage to right themselves again.

Not so fast, any more. Playing dead.

And last, he and his family live in plants, rather than under some shelter at ground level. This one was on yellow dead nettle; one on BugGuide was found in a rosebush.

In one way, he acts like the others; once he's found a safe spot, he tends to stay put. This critter is still in the dying dead nettle flower that I found him in. As soon as I post this, I'll take him out to the nettle patch and set him free.

UPDATE: I've been asked, on Facebook, how I know he's male. I don't. When I don't know, I randomly pick a sex, because I don't like calling critters with a mind of their own (no matter how feeble) an "it".

A female sowbug may have brood sacs at the base of some of her legs, seen when she's belly-up. I don't think I see any in the photo above.

And the first two pleopods of the five on the pleon (that triangular covering at the tail) of a male are elongated. In the photo, only the last three are visible.

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