Tasmania – Slaters

2014 February 26

My parents’ blueberry patch is in a swamp, very wet and lush. It is, quite literally, a jungle down there. Filled with plants that like it wet, like this “manfern” [1].

There is also a lot of what is locally known as “tea-tree”, which ranges in size from a scrubby little bush to fairly substantial trees. The bark is shaggy and kind of peels away from the trunk in big sheets.

And if you do peel away some of the bark, you are likely to find masses and masses of these:

(I left the picture large, so you can click on it for the full effect)

These are apparently Porcellio scaber, which are called “Slaters” in Australia, and “woodlice”, “sowbugs”, and quite a variety of other names in other parts of the world. They are probably the most common species of woodlouse in the British Isles, and by extension they have become one of the most common woodlouse species almost everywhere in the former British Empire. Mainly because of the older ships frequently using rocks and dirt for ballast, and therefore carrying along all the little crawling things living in the rocks and dirt.

This seems to be the only species of woodlouse in Tasmania, at least it’s the only one I saw. This one looks different at first, but I think it is just pale because it molted recently.

I’m not quite sure why they are called “slaters” specifically. It might be because they are slate-colored. And it might also be because they would be frequently found under old-style slate roofs.

Anyway, you’ll find them under rocks, in bark crevices, in woodpiles, and anywhere else that is dark, protected, and a bit moist. They mostly just eat things that are already dead and rotting, so they don’t usually cause harm in gardens unless they get so numerous that they have to eat everything they can. They don’t have many predators, as their shell-to-flesh ratio is pretty high and most predators don’t like to eat that much roughage. There is a species of spider that is particularly adapted to eating woodlice (its mouthparts are specially shaped to go around the armor), but I don’t think that spider species has gotten introduced to Tasmania yet. And so the slaters are almost completely unchecked by anything other than disease, and starvation, and simple crowding pushing them out into the dryness to die.

[1] I love manferns. They have trunks about 6-12 feet tall, and look very jurassic. When you see a clump of them, you can just picture a sauropod dinosaur suddenly poking out its head. Nobody is quite sure how old they get, because they don’t have distinct growth rings, but they evidently live hundreds of years. They are also hard to photograph, because they tend to grow in the densest, darkest, most jungly areas. If you get close enough for a flash to work, you can’t get the whole thing in frame, and if you back off enough to get them in the frame they generally are obscured by other foliage and are so dim you can’t make them out. This one happened to be on the end of the swamp, and was much more photographable than the others.

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