Porcellio Scitus Isopods

Most Porcellio are sold on size. This one goes the other way. Porcellio scitus is a small woodlouse and one of the least-known names in the genus: its scientific description rests on two animals collected on Madeira and measured in 1885.

What it is

Porcellio scitus Budde-Lund, 1885 is a species in its own right, not a colour morph of the rough woodlouse, P. scaber, which has its own care guide. Madeira is still the only locality given for it in Schmalfuss's world catalogue of land isopods, and for a time it was placed in the genus Lucasius. Beyond that description, most of what follows is the hobby's experience, not the textbook's.

Appearance and size

Budde-Lund describes an oblong, domed oval, slightly granular towards the head and finely pitted towards the tail, almost evenly grey with pale flecks drawn out lengthwise, mostly along the sides. The uropods, the two tail spikes, are small and flat. He gave its length as 6 mm, about a third of a full-grown rough woodlouse; sellers quote up to about 1 cm. With no adult range in any accessible source, the length box in our care panel is left empty.

Care and set-up

Nothing on its wild habitat is available in any accessible source, so set it up as a small Mediterranean Porcellio: a well-ventilated tub, most of the floor on the drier side, and one corner kept damp under sphagnum moss and bark. The 20 to 24°C in our care panel is a seller's figure, the only one we have found; we have found no humidity figure for it at all, so that box is empty too. A heated UK room sits just under that in winter, so run a small heat mat on the side of the tub on a thermostat, never underneath, as our heating guide explains. Build the base on flake soil, rotted hardwood and topsoil rather than coir, which holds water but feeds nothing, and check the lid and vents: at this size they slip through gaps a bigger isopod never could.

Diet

Leaf litter and soft, white-rotted hardwood are the staples, kept in the tub all the time. Like the rest of the genus it takes protein, so offer a pinch of fish flake or dried shrimp once a week and remove leftovers after a day. Keep calcium in permanently: a small piece of Malawi light limestone or cuttlebone supports clean moults.

Breeding

Nothing on its breeding is available in any accessible source, and Budde-Lund recorded no difference between the sexes; sellers call the hobby line a fast breeder. Sexing takes a hand lens. Turn an adult over: a male shows a pair of fine, pointed appendages running back along the middle of the tail section, the modified pleopods male woodlice mate with, while a female has none and carries her eggs and young in a brood pouch under her body. Our guide to sexing isopods shows what to look for. Start with ten or more and leave the substrate alone.

Who it suits

A keeper who likes small species and does not need a showpiece: at 6 mm in the original description, and up to about 1 cm by sellers' figures, this is an animal you watch with a lens. Sellers rate it hardy and easy, and few offer it. Our guide to the types of Porcellio covers the rest of the genus.

Your Porcellio scitus are counted out, as with every isopod order, with at least 20% extra. The box is double-walled, and the tub inside is vented and packed with damp sphagnum. Parcels leave Monday to Thursday by Royal Mail, and every order is covered by our live arrival guarantee.