TONKINBOLUS DOLLFUSII
Tonkinbolus Dollfusi: Captive Husbandry and general Observation on The Vietnamese Rainbow Milliped
Purpose
Tonkinbolus Dollfusi. The Vietnamese Rainbow millipede, Easily one of the most colorful and interesting looking species in the hobby and readily available too. Yet this is also one which poses many husbandry concerns, as it is actually one of the harder species to keep in captivity. Sadly the fact is, most of the specimens available through the majority of sellers are from wild collection. While it is not a at risk species, I firmly believe we should always be striving to captive breeding of our pets, for both our own education and protection of the wild populations.
Here, I am hoping to address some of the husbandry requirements to successfully keep (and breed!) this species from both my research and personal experience rearing my specimens. I have been keeping various species of milliped for many years now and whilst by no means a expert, feel I can speak confidently about their care and captive husbandry. Hopefully this will prove insightful to other Myriapod keepers.
Housing Millipeds, like most invertebrates, don’t have particularly demanding housing requirements. Any securely lidded container will be adequate for the majority of milliped species. A glass fish tank, a terrarium, or even a plastic tub like the Really Useful Boxes, will work.
The main things to consider when selecting your housing is the depth of substrate.
Millipeds need a deep, thick substrate to live in, as this is where they will spend the majority of their time, retreating underground during the day and burrowing to remain undisturbed to moult. In that vein, a plastic tub like the RUB is easiest, as they offer the option to provide substrate depth right to the top of the container. They are however the least attractive option. A fish tank offers the same functionality but with a nicer overall finish being made of glass, while on the negative side being harder to move and more fragile than the plastic box. Either of these housing solutions can work perfectly, so it comes down to your personal preference here!
Substrate
So I’ve talked about the kind of container for keeping your T. Dollfusi. Now lets cover the substrate you put in the container for them to live in.
This is arguably one of the most important things to consider when preparing your set up. Millipedes live in the substrate, breed in the substrate, moult in the substrate, lay their eggs in the substrate and eat the substrate. If it’s not up to scratch, they’ll not survive very long at all.
So what to use?
Well, there’s lots of options.
We’ll come on to where is good and where isn’t to get the supplies from in a moment.
For the bulk of the substrate, the main common choices are Coco-fibre - also known as Coir - and topsoil. For the purposes of this write up I’m ignoring premixes such as ABG. They are fantastic and I have nothing against them, but here we are focusing on making substrate mixes yourself. Coir is less nutritious, with virtually no nutrients in it for the milliped, but comes in a dried block, so is invader free. Topsoil is simpler, and becomes “muddy” less easily, but is more nutritious and generally cheaper. Be wary if choosing soil, to be sure there are no pesticides or any inorganic fertilisers included in the soil.
The second part of the substrate is the food. Because millipedes eat the substrate, a major consideration must be the nutritional value of the substrate itself. The main diet of millipedes is rotting wood and rotting leaves, so the easiest - and best - thing to do is to collect rotting wood and leaf litter from outside. Be careful to collect it from somewhere you can be confident has not been treated and is as natural as can be. The last thing you want to do is introduce pesticides or fertilizers in to your enclosures on the food!
I collect from a local woodland, which I know is left wild. I watch for local fauna and wildlife - if the local isopods and millipedes are in abundance, it’s a good sign whatever you are looking at is quite safe.
The final component of any good substrate mix is calcium. This you don’t need mountains of, just a source to make sure your millipedes are able to get enough. It is essential for them to build their exoskeletons. The easiest way to do this is to scrape a cuttlefish bone across a knife to create calcium dust. Let this mix in to your substrate and leave the piece of cuttlefish in there too on the surface. The Millipedes will be able to chew it when needed.
Now, having collected a nice heap of hardwood leaves and rotting wood - as wet and soft as you can find - mix it in with your chosen substrate medium. Mix it about 50/50, I find that a good messy mix with enough food to last months. Then as time goes on simply add more leaf litter and bits of wood to the surface of the substrate. The millipedes will do their job and break it down in to the substrate from there. This mix will last weeks, and supplementary food stuffs will then be offered once a week. I’ll talk more on supplementary foods in a later section.
Another note on substrates. Here I’ve been trailing something new from Arcadia, their Bio-Revitaliser. It is a part of their Earth Pro range and is billed as a totally safe, natural fertilizer for vivariums. In the product description it also mentions it contains a fantastic range of vitamins and nutrients for bioactive vivarium custodians. I realized this is actually a perfect addition for the milliped set-ups, as those are the exact things I am looking to ensure the substrate mix contains. I’ve been using it a while and can highly recommend it.
Temperature
Tonkinbolus Dollfusi are a tricky species, as I alluded to in the opening. Temperature requirements are a big part of this.
I’ve found they are particularly temperature sensitive, and careful regulation of heat is critical to their husbandry. I heat T. Dollfusi with heat mats, but there are various
options available depending on your chosen housing solution from the previous Chapter. Other options include Ceramic Heat Emitters, suspended above the enclosure, or heat cable if your keeping your bugs in a rack style set up. The tricky part, whatever your chosen heating system, is getting the temperature right. Being from warm, stable forests, they have not evolved to handle large temperature changes and as such do
best when kept at a stable temperature. Just a touch too warm, and they’ll die off quickly. Just a touch too cold, and they’ll last longer… But still die off eventually.
The exact range I’ve found through both research and experience to work, sits at 72 to 82F or 22 to 27c. I keep ours at a pretty stable 24c.
If you are opting for the heat mat or heat cable solution, the best way to position your heaters on the side of your housing. Many heat mats are especially designed to go below a enclosure, but with millipedes they must be on the side regardless. The reason for this is such:
Millipedes generally are only active in the cooler night time period in the wild, and burrow to escape the heat and predators of the day. If your millipede is feeling too warm, by instinct it will burrow to escape. If your heater is below the container, the millipede will be getting closer and closer to the heat as it burrows… so will continue
burrowing down to escape it… getting closer to the heat again… you see where this is going?
On top of that, with the large amount of substrate you are hopefully using the heat from a heat mat won’t penetrate through to the surface anyway. Heat can however build up causing what is called Thermal Blocking. In the worst case scenario this can actually lead to fires as the heat builds up and the mat overheats, then melts causing electrical shorts...
Regardless of your chosen heating system, it is imperative that you use a thermostat to regulate your heater. The thermostat will ensure the heat is consistent, and holds within that narrow temperature range above to allow your T. Dollfusi to thrive, and
will also protect you if anything goes wrong with your heating equipment. They act as both a controller for the heater and a safety precaution.
Feeding
I’ve touched on this already in the substrate chapter, but I’ll try to cover it a bit more thoroughly here. Millipedes eat substrate, so ensuring the substrate has enough food in the mix is essential. In a ideal set up, the majority of the food comes from hardwood leaf litter. Oak, Beech, maple, hickory, cherry, and birch are all good. In reality of course it can be hard to tell which trees the handful of rotting leaves you’ve just picked up came from so the main thing to look out for is pine. Pine contains irritant saps which can be toxic to insects. The same goes for rotting wood you collect. Most trees are fine, and if well rotted it makes little difference. Hardwoods are the most nutritious, but also rot slowest so are
often harder to find. Pine is best avoided for the same reasons but cottonwood, oak, aspen, maple and so on are all safe.
When it comes to supplementary foods, many species will happily take fruits and vegetables too. These aren’t necessary, but are a good way to help get additional nutrients in to your inverts. However, T. Dollfusi in my experience do not readily take fruit or veg, and will totally ignore usually favoured food stuffs like cucumber and banana. I have found they turn down anything but leaves and rotting wood. Because of this they require a regular supply of fresh (well… fresh but also decaying) leaves and pieces of wood to eat.
Breeding
Ah, breeding. The end goal of many hobbyists and, especially with this species, quite the achievement. Although it should be a easy species to breed, and as a species that is quite common in captivity, it seems that captive bred specimens are rare.
The biggest piece of advice really when it comes to breeding any milliped, is to give them space. They do not appreciate being dug up, handled regularly, or otherwise disturbed. When mating the 2 millipeds will coil around themselves, their heads facing each other so that the gonopods can make contact so the male can transfer the
spermatophore to the female.
The eggs are laid in the substrate, so it’s actually best to change the substrate as rarely as you can. The eggs are huge for this species, much larger than even much larger millipedes. The young are short and thick, being much smaller than the egg
they came out from but still quite large by hatchling milliped standards. It’s best to leave the young with the adults until they’ve had a few moults, to allow them to build up the necessary gut bacteria to digest their food correctly. They get this from the adults by eating their droppings, which is one of the reasons not changing the substrate is so important. The young reach adulthood in approximately 30 months, but are sexually mature sooner.
General Observations
This is a secretive species that does not take kindly to handling, so if you are looking for a bug to handle and interact with these are likely not for you. They are capable of quite a significant defensive excretion, capable of turning skin iodine pink very quickly. This is a minor chemical burn and ought to be avoided as much as possible - it won't wash off.
However, to the determined keeper willing to look but not touch, they can be a immensely rewarding species to keep.