Since we moved into an upper floor apartment (versus the basement unit we had previously), we’ve had very few insects pay us a visit… and even the arachnids have been scarce. I’m of the mind that these sorts of critters belong outside, so I’ve found this situation very satisfactory. This spring, however, we had an encounter with a particularly interesting type of beast – a sowbug (also called a wood louse). We actually saw three of them, but I managed to capture an image of one in what is possibly the very worst photo ever recorded with a modern phone camera:

Sowbugs (Oniscus asellus), I’ve since found while perusing the Internet, are ALWAYS confused with pillbugs (Armadillidium vulgare – isn’t that the best name ever?). They are not the same, however. Pillbugs have rounder bodies than sowbugs, and they are capable of curling into a ball, which has earned them the nickname roly-poly. Sowbugs can’t pull off that same stunt – their bodies aren’t designed for rolling up.

We may call them “bugs,” but sowbugs are not insects – they are terrestrial crustaceans. That means they have a bit more in common with a shrimp than an earwig. Sowbugs have seven pairs of legs, rather long antennae, and armored bodies that can reach a length of up to 15 millimetres (0.6 inches). They can’t bite or sting or do any damage inside the home (they definitely don’t care about what’s in your pantry). In fact, the last place they want to be is indoors, because they cannot survive for long there. They primarily feed on decaying plant matter and really would prefer to be crawling around in wood mulch or in some dead leaves in your garden. They also have gills, so they need moist, damp environments to survive. Typically, kitchens and living rooms don’t fit that bill.

Another pretty neat thing about sowbugs? Like many other crustaceans belonging to the order Isopoda, they give birth to live young and carry them around in a brood pouch called a marsupium. I propose that from now on, we stop calling them sowbugs, which is totally inaccurate, and use the more appropriate moniker “land shrimp kangaroos.” Oh wait, there are already kangaroo shrimp (Dugastella valentina), so that could be a tad confusing. Land shrimp wallabies? 😉

So, next time you see a sowbug in your house, gently take it outside and marvel at just how fascinating the natural world is. Then head inside and ponder why the heck it – and two friends – had taken up residency behind the stove. Hopefully there isn’t too much decaying wood back there or we’ve got some renovations to do….

Have you ever seen sowbugs or pillbugs in your garden or home?

For more information about sowbugs, check out this article from the City of Edmonton.