Quick answer: Rubber Bee isopods (Cubaris sp. 'Rubber Bee') are a Thai species of around 15mm with a yellow front, a dark navy midsection and a clean white rear. They are not a Rubber Ducky. Keep them at 21 to 27°C, in the lower to middle part of that for choice, which in a British house means a heat source on a thermostat for most of the year. Give them damp air rather than a wet tub, humidity around 70 to 80% at the damp end with a drier side to retreat to, build a deep substrate they can eat with limestone worked through it, and vent the tub without turning it into a wind tunnel. Medium difficulty, a slow-to-moderate breeder, and neither a first isopod nor a first Cubaris. Ours are captive-bred here in the UK.
The first thing most people ask me about the Rubber Bee is the question I answer on the Rubber Bee listing as well: is it just another name for the Rubber Ducky? It is not, and the answer is on the animal itself. Look at the back end. A Rubber Ducky is yellow and dark and then stops; a Rubber Bee carries on into a white tail, so the whole body reads yellow, navy, white from front to back. That third colour is what you are paying for, and it is why this animal sits in the premium tier of the Cubaris we keep. It is also a more active animal than the Rubber Ducky, and one you will see by day, which in a genus that mostly lives under things counts for a great deal.
What a Rubber Bee Actually Is
'Rubber Bee' is a trade name for an undescribed Cubaris from Thailand, and that sentence carries more uncertainty than it looks. Nobody has formally described the animal, so there is no scientific name beyond the genus, no type specimen and no published collection locality. Even the genus is provisional: Cubaris in the hobby is a label of convenience for a group that taxonomists have flagged as needing revision. Thailand is what the trade reports, and no source offers anything more precise. Nobody has published where in Thailand it lives either, so I keep it as a limestone animal like the rest of the Thai Cubaris, and the cave figures further down are the nearest measured proxy anyone has. What we do know is what it looks like and how it behaves in a tub, and after keeping it here that is what this guide is built on.
The name does what hobby names usually do. The front half is a Rubber Ducky's, a yellow face with a dark band behind it, and the yellow and dark together presumably suggested a bee. Adults reach around 15mm, a touch under a Rubber Ducky's 15 to 20mm, with the compact rounded build of the genus and the habit of rolling up when bothered. The pattern is not fixed at birth: the full three-colour run firms up as the juveniles mature through their moults, so do not judge a young animal by its colour yet. There is one look-alike worth knowing about. The Chinese Cubaris sp. 'Daxin Tricolor' carries a similar three-part run, with a deeper orange at the front and a paler, more translucent tail rather than a solid white one, and at least one reference site files that animal under a different genus altogether, which tells you how loose these labels are. For the limestone country the Thai group is reported from, our guide to Cubaris in the wild covers the habitat and why it matters.
Rubber Bee or Rubber Ducky?
Side by side the two are easy to separate, and the tail is the tell. On a Rubber Ducky the dark colour carries through to the end of the body; on a Rubber Bee the last third is white, sometimes with a touch of cream in it, and the boundary between navy and white is sharp. The Bee is a shade smaller, and its dark segments carry fine pale yellow flecks. The behaviour is different too. Rubber Duckies are night animals that spend most of their lives under cork, and our Rubber Ducky care guide says as much; Rubber Bees are out more than most premium Cubaris, and out in daylight, grazing the surface of the litter where you can watch them. It is the difference between a species you keep and a species you see.
Keep them apart all the same. Two Thai Cubaris with the same front half in one tub is a sorting job you will never finish once there are mancae in it, and I know of no test of whether the two would cross. Give the Rubber Bee its own tub; our guide to keeping different isopods together covers when mixing works and when it does not.
Warm, Not Hot: Temperature in a British House
Our care panel gives 21 to 27°C, and the animals do best in the lower to middle part of that. Where the band comes from is worth knowing, because "tropical" misleads people here. A limestone cave in Southeast Asia is not hot. When the Dark Cave at Batu Caves in Malaysia was surveyed in 1967, a survey that recorded terrestrial isopods living in it, the interior held a mean of 24.5°C and moved between 23 and 25°C across the whole year, while the forest outside reached 29 to 30°C most afternoons. The habitat is stable and saturated rather than hot.
A British home does not get there on its own. Measured across 823 English houses, the heating-season average is 19.0°C, December sits at 18.1°C, and even July and August only reach about 21.5°C. So for most of the year a Rubber Bee needs help, and the help has to be regulated. I run a heat cable along the back of my racking on a thermostat, which lifts a row of tubs into the low twenties and holds them there. An unregulated mat is what cooks a colony. Heat the tub into the range and no further: there is no evidence that pushing past the mid twenties helps, and in the one feeding trial that has tested it, raising a temperate Porcellio from 20 to 28°C roughly doubled its mortality. Nothing of the kind has been measured on a Cubaris at all, which is worth remembering whenever anyone quotes you a precise figure. In a July heatwave the job reverses: switch the heat off, move the tub to the coolest room and keep it out of the sun. Our heating guide covers the equipment and the numbers behind it.
Damp Air, Not a Wet Tub
Water loses more Rubber Bee colonies than anything else, with uncontrolled heat close behind. The species wants humid air, and the mistake is to give it wet substrate instead: a waterlogged tub brings failed moults and sudden losses. Aim for substrate like a wrung-out sponge. Hold the damp end at around 70 to 80% with sphagnum and a light misting, and leave the far end drier under dry leaf litter so the animals can choose. The drier end has to be truly drier. The only woodlouse anyone has measured for this, a temperate Porcellio, shows no response to humidity at all unless part of its enclosure sits below about 65%, and while nobody has run that test on a Cubaris, a tub that reads 75% at one end and 80% at the other offers one condition with a label on it rather than a choice. When in doubt, err slightly drier and lift the ventilation.
Ventilation is the other half of the same question, because you cannot hold a drier end in a sealed box; the moisture equalises within hours and the gradient disappears. Cave Cubaris want less airflow than a Spanish Porcellio, but never none. My own tubs carry large vents, two to four on each, and an oscillating fan moves air across the racking through the day; the Cubaris get the gentler end of that, and they still get it. What they must not have is still, wet air. Our ventilation and humidity guide goes through the mechanics, and the mould guide explains what happens in a tub where the air stops moving.
Substrate, Limestone and Calcium
These are limestone animals, and the substrate has to say so. Build it 5 to 8cm deep on organic topsoil, flake soil and white-rotted hardwood, a base the animals can eat, rather than coco coir, which holds water and feeds an animal that eats its substrate nothing. Work crushed limestone or oyster shell through the mix and sit a few chunks of limestone on top where they can graze it; a piece of cuttlebone alongside does no harm. For a Cubaris calcium is part of the habitat rather than a supplement, and a colony short of it fails moults and stops breeding. Our limestone guide covers what to buy and what to avoid, and the substrate guide has a working mix. Over the top goes a deep layer of hardwood leaf litter, with cork bark and rotting wood for cover, because a Rubber Bee without cover goes under and stays there.
Feeding
Leaf litter and decaying white wood are the diet and should never run out; top them up as they vanish rather than to a timetable. On top of that base I offer a little vegetable once or twice a week, courgette, carrot or sweet potato in small pieces, and a pinch of protein such as fish flake or dried shrimp about as often. I feed a wide variety across the whole range of foods we sell, because a varied diet is the thing I have found does most for breeding, and the Rubber Bee is no exception. Lift anything uneaten within a day or two. At this humidity leftovers turn to mould fast. A springtail culture seeded from day one stays ahead of the mould, and on an animal in this tier it is cheap insurance.
Breeding, and the Patience It Takes
Breeding is slow to moderate, and the shape of it is the same as the rest of the premium Cubaris: a new group takes its time to settle, then, once conditions have been held steady for a few months, it starts producing and carries on close to year-round. Females brood their eggs and release live young, and the mancae come into their colours as they mature through their moults, so do not judge a line by its babies. The most useful thing you can do is nothing: hold the temperature, keep the damp end damp and the calcium constant, and resist the urge to dig through the tub to see how it is going.
Start with a group. I start my own colonies at twenty or more animals where I can, because a bigger group settles faster and gives a better spread; with a premium Cubaris the budget usually decides, and ten to fifteen is the realistic floor. Our guide to how many isopods to start with sets out the arithmetic. Give a new group a few months before you expect anything, and a year or more before you expect to split it.
Is the Rubber Bee the Right Isopod for You?
Not as a first isopod, and not as a first Cubaris either. It is rated Medium on our panel, and what that means in practice is that it punishes fluctuation: a week in a cold room, a tub that got overwatered, an afternoon left in the sun. The genus as a whole is not a beginner genus, and I would point a new keeper at a Porcellio or an Armadillidium first. Within Cubaris the door in is the Panda King, which forgives the mistakes you will make while learning what a cave species wants, and breeds while you learn; the hardy Cubaris murina lines do the same job at a gentler price. Come to the Rubber Bee once you can hold a tub steady for a few months without thinking about it. Our complete Cubaris care guide is the place to learn the genus.
It suits the keeper who has kept a Rubber Ducky and wants more colour and more to watch, and the collector building a shelf of Thai patterned species alongside the Bumblebee. It is neither a cleanup crew nor an animal you handle. Once settled, it gives you a colony of small three-coloured animals grazing in the open in daylight, which most Cubaris will not.
Frequently Asked Questions
Is the Rubber Bee the same as the Rubber Ducky?
No. They are kept and sold as separate species, and they look and behave differently: the Rubber Bee finishes on a white rear where the Rubber Ducky stays yellow and dark, runs a little smaller, and is out in daylight far more. Nobody has described either animal scientifically, so 'separate species' is the hobby's working reading, but it is a reading the animals support.
How big do Rubber Bee isopods get?
Around 15mm as adults on our figures, a touch under the Rubber Ducky's 15 to 20mm.
Do Rubber Bee isopods need a heat mat?
For most of the British year, yes, and always on a thermostat. An English home measures about 19°C in the heating season and 21.5°C in July and August, and the ideal band starts at 21. A side-mounted mat or a heat cable on a thermostat lifts the tub into the low twenties and holds it there.
How long do Rubber Bee isopods live?
No published figure exists for this animal. Our complete Cubaris guide puts the genus at two to three years in good conditions, and I would plan on that.
Can I keep Rubber Bees with Rubber Duckies?
Do not. They share a front half, and once there are mancae in the tub you will never sort them again. I know of no test of whether the two would cross, and it is not a test worth running on animals in this tier. Give each its own tub.
Why is it called a Rubber Bee?
The front half is a Rubber Ducky's, the yellow and dark together read as a bee, and the white tail came along for the ride. Hobby names describe the animal; they are not taxonomy, and there is no more official name to give you.
Where to Start
If the thermostat and the patience have not put you off, the Rubber Bee listing carries current stock, and our Cubaris range has the Rubber Ducky and the rest of the Thai group beside it. Every colony we send is captive-bred here in the UK, travels in a ventilated deli tub on damp sphagnum inside a double-walled box, is dispatched Monday to Thursday so nothing sits in the post over a weekend, and comes with our live arrival guarantee.
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