Armadillidium granulatum 'White Pearl' Isopods

Take the bright yellow spotting off a granulatum and something interesting happens: the shell itself becomes the feature. The White Pearl is a pale form of the Spanish Yellow Spanish granulatum in which the dark pigment and the yellow markings are both dialled right back, leaving a soft, pearlescent cream-to-white body. Without the usual spotting to catch the eye, what you notice instead is the granulated, faintly pebbled texture that gives the species its name, picked out cleanly across a pale, almost ethereal animal. Against dark substrate the effect is quietly striking rather than loud.

It is an albino-type colour form rather than a random one-off. The pale look comes from reduced melanin, a recessive trait isolated from standard granulatum stock through patient selective breeding, so a White Pearl colony kept on its own breeds true and holds the colour generation after generation. Cross it back to the spotted wild type and the pattern returns in the offspring, which is worth knowing if you want to keep the line clean. It sits alongside the vivid Orange Naranjito as one of the more collectable granulatum forms.

Underneath the pale coat this is the same hardy, forgiving Armadillidium granulatum, one of the larger and easier Mediterranean pill bugs, so the premium look comes with accessible care. Big adults reach around 20 to 25 mm, they are prolific once settled, and they conglobate into a tight sealed ball when disturbed, the classic pill-woodlouse trick, here on a pearl-white body. For a keeper who wants a rare-looking morph without a rare morph's fussiness, it is an easy recommendation.

Being a dry-country Spanish species, it wants a moisture gradient rather than uniform damp. Keep the tub around 50 to 70%, one lightly moist corner under sphagnum and leaf litter with the rest allowed to dry between mistings, and drill cross-ventilation into a five to ten litre clip-lock tub to keep the air moving. Normal room temperature works the year round, roughly 15 to 26°C. For substrate use a living base of flake soil, rotted hardwood and organic topsoil at least five centimetres deep, topped with magnolia and oak leaf litter and cork bark; keep a coco-coir-only base out of the mix, since it holds water without feeding anything, and leave cuttlebone or crushed eggshell in for constant calcium, which matters all the more for keeping pale moults clean.

Feeding is the standard detritivore spread: leaf litter and rotting wood always down, soft veg such as courgette, squash and sweet potato a few times a week with leftovers removed promptly, and an occasional pinch of protein to keep a breeding colony ticking. As with any Armadillidium they will nibble soft plants in a bioactive setup, so plant tough. Breeding needs little beyond the right gradient and steady calcium: females release live miniatures, and the pale colouring shows from early on, so a colony grows into a striking pale display over a season.

There is more on how these colour forms arise in our note on isopod genetics, colours and morphs, and the rest of the genus is in the Armadillidium collection. Every order is captive-bred, packed in a double-walled box around a ventilated tub of damp sphagnum and posted Monday to Thursday by tracked next-day Royal Mail, with a small overcount and a live-arrival guarantee on every parcel.