The Bumblebee Millipede, Anadenobolus monilicornis, is a small Caribbean millipede, black to dark brown with a yellow to lime-green band on every ring and red legs, and keepers rate it among the easiest millipedes to keep and breed. Its care comes down to a damp bed 5 to 8cm deep of flake soil, rotted hardwood and leaf litter, which is its food as well as its home; warmth of 20 to 26°C, which most homes fall short of from autumn to spring; calcium at all times; and a tight, ventilated lid, because it climbs. The animals themselves are on our Bumblebee Millipede listing.
The name and what sits behind it
Carl Oscar von Porat described it in 1876, in a paper on exotic myriapods published by the Royal Swedish Academy of Sciences, as Spirobolus monilicornis; the brackets in Anadenobolus monilicornis (Porat, 1876) record its later move to another genus. It belongs to the Rhinocricidae, a family of round-bodied millipedes in the order Spirobolida. The epithet joins the Latin monile, a necklace, to -cornis, horned: necklace-horned, describing antennae that look like a string of beads.
It is the bumblebee millipede both in the pet trade and in Florida, where it was introduced, and Florida's extension services also call it the yellow-banded millipede. The male it was described from came from an unspecified site in Brazil, and the species has not been recorded in Brazil since, according to the most detailed modern account, Rowland Shelley's 2014 review in Insecta Mundi. Shelley also suggested that the Caribbean Anadenobolus may all be one variable species, in which case an older name, arboreus (Saussure, 1859), would take over, but MilliBase, the world millipede database, still lists A. monilicornis as accepted.
Appearance, size and range
Adults are black to dark brown, with a band at the back edge of every ring that runs from yellow to lime green, and red legs and antennae. Shelley gives about 45 body rings, a length of about 45mm and a maximum width of about 4.2mm, while general references give 25 to 30mm. The 25 to 45mm in my care panel spans the two. Care sheets quote far larger animals, but I have found no measured specimen behind those figures. Disturbed, it coils into a flat spiral; rolling into a ball is what pill millipedes do.
It is probably native from Hispaniola and Puerto Rico down the Lesser Antilles to Trinidad, eastern coastal Venezuela and Suriname, and people have carried it to Florida, Bermuda, Barbados, the Cayman Islands and Jamaica. Its first Florida record, from Pine Island in 1959, did not lead to an established population, but by 2001 it was in the Florida Keys in huge numbers. In Florida it is a household nuisance rather than a crop pest, with thousands recorded on walls, floors and ceilings in the worst infestations and animals climbing house walls to the second storey. Advice for Florida householders notes that the ones that get indoors usually dry out and die within a day or two, which tells you how much it depends on a damp bed.
Captive monkeys have been recorded rubbing these millipedes through their fur, and in Puerto Rico in 2018 a wild grackle was watched rubbing one against its wings, back and belly. I have found no study of what an animal gets from this particular millipede.
Setting up a bumblebee millipede enclosure
Keep a group: one keeper suggests at least six to start, and keepers say a dozen or more fit comfortably in about 40 litres. Whatever the size, the tub needs depth for the bed, headroom above it and a tight, ventilated lid, because this is a climber that will find any gap.
The bed is food as well as shelter. Lay it 5 to 8cm deep, from flake soil, white-rotted hardwood and organic topsoil, with pieces of rotted wood through it and a layer of crushed leaf litter and whole leaves on top. Hardwood only, no pine or other conifer. Keep it damp through its depth without the top sitting wet: a squeezed handful should hold together, not drip. Water the bed when it starts to dry rather than misting the air. My care panel gives 70 to 80 per cent humidity, but the bed is the thing to watch.
Temperature is 20 to 26°C, the band in my care panel. That is a keepers' range, since I have found no study of this species' temperature needs. A heated English home averages about 19°C through the heating season, so from autumn to spring most rooms fall short, and the answer is a heat mat or heat cable on a thermostat, on the side of the tub, never underneath. Millipedes burrow away from conditions they dislike, and heat from below takes that refuge away.
Once the bed is built, leave it alone. A millipede that disappears for days is usually moulting in a chamber underground, and digging it out then can kill it; our guide to millipede moulting explains why.
What bumblebee millipedes eat
The bed is most of the diet. Keepers feed this species rotting hardwood and hardwood leaves, and warn that the leaves need to be well decayed. Much of what a detritivore gets from a leaf is the fungi and bacteria growing through it, as our piece on fresh versus well-rotted leaf litter explains. Top up the litter and wood as they disappear.
Beyond that it takes a wide range: our listing gives leaf litter, dead wood, fallen fruit, seeds, fungi and dead invertebrates when it finds them. In practice, offer small pieces of vegetable or fruit two or three times a week, removed before they mould, and a little protein once or twice a week. Do not feed daily, because uneaten food left to rot invites mould and mites.
Keep calcium in the tub permanently, because a millipede's exoskeleton is hardened with calcium and every moult draws on the supply. Cuttlebone is the usual choice, and crushed oyster shell can be worked into the bed too.
Breeding and the young
Keepers describe it as one of the easiest millipedes to breed, to the point that one keeper's only suggestion for stopping it was to separate the sexes. A warm, damp, deep bed with plenty of rotted wood and calcium is what it needs; if a group is not breeding, our guide to why millipedes fail to breed runs through the usual causes.
Care sheets say the female guards her eggs in a nest, but the only source I could trace for it is a general zoology textbook writing about millipedes as a group, and a UK zoo describes eggs laid singly through the leaf litter. Care sheets also report the young eating the adults' droppings, and describe them as close to colourless for up to six months, though one keeper calls them light brown. Either way, a tub that seems to hold only adults may be full of young. Leave the bed alone: eggs and the smallest young develop out of sight, often inside chambers that digging breaks open, and the droppings are part of what is on the menu down there. Keep the generations together and thin the group only when it has clearly outgrown the tub.
Handling and the defensive fluid
This is a millipede to watch more than to hold. If you do pick one up, let it walk onto a flat hand rather than pulling it off the bed. Handled roughly it can release a defensive fluid from pores along its body. When Shelley reviewed the species in 2014 the chemistry of that fluid had not been worked out, and I have found no analysis since. Its relative Anadenobolus putealis produces two benzoquinones, the same class of compound other millipedes in its order use, so treat this one's fluid the same way.
On hands it is a nuisance; in an eye it is not. The fluid stains skin brown, can irritate if left on, and in an eye causes a chemical burn that needs treating. Wash your hands with soap after handling and before you touch your face, and supervise children, since the published series of millipede eye injuries was mostly young children. If any gets in an eye, rinse it out and get it looked at promptly. Our article on whether millipedes are dangerous sets out the evidence.
Who the bumblebee millipede suits
It suits a first-time millipede keeper who wants something small, colourful and active, and anyone who would rather keep a breeding colony than a single pet. It is a poor choice if you want a large animal to handle. Both captive-bred and wild-caught animals circulate in the trade under this name, and our listing makes no blanket captive-bred claim.
Frequently Asked Questions
How long do bumblebee millipedes live?
Three to five years is the usual estimate, from care sheets, a zoo and a keeper. I have found no published study of how long this species lives, and the occasional claim of seven or more comes with nothing I could trace behind it. Our guide to how long millipedes live puts mid-size species at about five years. A group bought young gives you the most years.
What do bumblebee millipedes eat?
Mostly their bed: rotting hardwood and well-decayed leaf litter. Add small pieces of vegetable or fruit two or three times a week and a little protein once or twice a week, remove fresh food before it moulds, and keep a calcium source in the tub permanently.
Are bumblebee millipedes good for beginners?
Yes. They are small, hardy and quick to breed, keepers rate them among the easiest millipedes to keep, and my care panel lists them as Easy. Get depth and warmth right: give them a damp bed 5 to 8cm deep, keep them at 20 to 26°C through the colder months, and leave the bed undisturbed.
How big do bumblebee millipedes get?
Most adults are 25 to 45mm long and about 4mm wide. General references give 25 to 30mm and the most detailed scientific account about 45mm, across around 45 body rings; the 25 to 45mm in my care panel covers both. I have found no measured animal behind the larger figures that circulate.
Are bumblebee millipedes poisonous?
They have no venom and cannot bite or sting, but they do have a chemical defence: a fluid released from pores along the body, which stains skin, can irritate it, and in an eye causes a chemical burn that needs treating. Blindness is possible but rare, according to medical references, so rinse any secretion out of an eye and get it looked at promptly. Wash your hands with soap after handling and supervise children.
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