Batman Isopods (Ardentiella sp.)

The genus name Ardentiella comes from the Latin ardens, meaning burning or fiery. It was chosen because so much of the group arrives in black, yellow and red. Batman is the one that skips the fire. The colouring is predominantly dark, and what pattern there is works as contrast rather than colour. The build is typical of the genus, flat instead of domed and carried on longer legs, made for moving across surfaces rather than digging down through them.

Adults reach somewhere around 18 to 20mm, large by isopod standards, though that is our own measurement and not a published figure, since almost nothing has been written about this morph outside shop listings, ours included. The animal is Ardentiella sp. 'Batman', still sold in plenty of places as Merulanella sp. 'Batman' after a recent revision lifted it clear of Merulanella, and both names remain in trade use. It is Vietnamese, part of the tropical South East Asian group, and Batman is a hobby lineage name, not a described species.

Batman sits at the opposite end of the genus from the rest of what we keep. Our Red Diablo leads on red, our Phoenix carries red running through yellow and black blotching, and our Tri Colour carries neat banding in red, yellow and black. The Scarlet is brighter again. Batman is the counterweight, and a shelf of red and yellow is better for having one dark animal on it. The rest of our wider Ardentiella range falls between those poles.

Two vents, facing each other

Start with the box, because the box is what a colony lives or dies by. Fine mesh goes into one wall and more fine mesh into the wall opposite, so air has a way in and a way out, crossing the interior instead of pooling. One vent alone leaves dead volume behind it. Damp air with nowhere to go kills Ardentiella more quickly than any other mistake, and anything that pushes humidity up tends to shut airflow down, which is why the vents come before the water. Humidity wants to be roughly 60 to 75 per cent, damper at one end than the other, never soaked. Temperature should sit between 19 and 26°C, best held around 21 to 24°C. They suffer above about 26°C, so a house that bakes in summer needs sorting before you order.

Sitting in their own frass does for them as surely as bad air does, and it is the slow failure that catches keepers who have got everything else right. Keep the box clean, and let a springtail culture live in there with them to deal with the small mess continuously. Give them depth, eight centimetres of damp living substrate at the very least, holding humidity without turning to swamp, under a generous layer of leaf litter they eat as readily as they shelter in. Leave calcium in the tub at all times: cuttlebone, crushed limestone or oyster shell. White rotten wood makes up the bulk of the diet, with a little vegetable and the odd protein feed on top.

The lid is the weak point

Glass and smooth plastic are no barrier to Ardentiella. They walk up both the way a cockroach does, mancae just as well as adults, and the lid must seal with nothing open at the clips or around the vents. They use height, so a taller container is the sensible shape and cork bark and branching stay in constant service. Conglobation is in the repertoire but comes out rarely enough that you should file them under fast flat climbers. Ours are captive-bred and moderate to keep, well clear of wild-caught Ardentiella for difficulty, but none of that makes Batman a beginner isopod. Keepers who want the genus without the difficulty curve tend to start on Ember Bee, and our Ardentiella care guide covers the husbandry in full, written around Red Diablo but true across the genus.

Damp sphagnum lines a ventilated deli tub, and a double-walled box goes round that. Boxes go out Monday to Thursday, nothing later, on a tracked Royal Mail next-day service delivered before 1pm, so no colony of ours is stuck in a depot on a Sunday. Spares ride along above the number ordered, under our live-arrival guarantee.