Basic Millipede Husbandry

Millipedes, of the class Diplopoda in the order Myriapoda, are a diverse group of creatures found on six of the seven continents. Their history stretches back to the Silurian Period, and they have been decomposing organic matter the world over ever since.

For many, millipedes are semi-interesting oddities in the world of "bugs", but for a select few they are fascinating to observe and study, whether in the wild, in a jar of ethanol, or in captivity. When properly cared for many species will breed in captivity, and to crack the code on one of the more difficult-to-breed species is both a valuable contribution to the hobby of keeping these creatures and to the scientific record if the details are properly recorded.

Note that these care instructions are by no means a definitive guide, and remain but basic notes on husbandry. See specific species reports in the families pages for more information on a given species.

1. Enclosure

For the containment of any wild creature a suitable cage or habitat is necessary. Millipedes are undemanding in this sense, and it is generally recommended that such enclosures be 2-3 times the length and width of the longest specimen that will be inhabiting it. Depth of the enclosure should allow, in general, for the substrate to be as deep as the longest specimen, though this rule isn't hard-and-fast: for example, a 12-inch/30.5 centimeters long Sechelleptus argus does not require the same amount of depth (though if provided it is nonetheless appreciated). For species that tend to enjoy climbing making sure the enclosure has the space to also contain some upright branches or larger logs is recommended. If a high density of specimens is going to be maintained, or breeding is wish to be done, it is recommended to increase the enclosure size two to three times depending on the fecundity of the species in question.

Plastic, glass, and acrylic enclosures all work well and the make does not matter; anything from ten gallon (38 liters) aquariums to custom made acrylic cages to plastic bins serve the purpose equally well, so long as they meet the needs of the species in question.

2. Ventilation, Moisture, and Temperature

Millipedes in general require moist substrate; that is, moist to the touch, but not so wet that one can squeeze water droplets out of the substrate. The amount of moisture required depends on the species, but this is the general rule of thumb. Specific humidity numbers, while often touted as being very important, do not matter so long as the soil moisture is appropriate and ventilation is not excessive.

While some species can be kept without ventilation for some time, this is not recommended, and depending on the enclosure and the species in question specimens will oftentimes suffocate or poison themselves with fumes from their toxic secretions (a problem with many polydesmids). Therefore, some ventilation, whether a few holes in the lid or a well-placed screen vent, is recommended; if you are having to moisten the substrate more frequently than once or twice a week, it is likely best to reduce ventilation. If the substrate does not start to dry out within a few months, or the substrate becomes and remains muddy for long stretches of time/pools in the bottom of the enclosure, an increase in ventilation is strongly recommended. Cross ventilation is not required typically.

The temperature required depends on the species in question. For example, many polydesmids are more sensitive to overheating, and as such often require cooler temperatures. In general, room temperature (70°-78°F/21°-25.5°C) is suitable for most round millipedes, though again one must consider the species in question to determine the proper temperature. It should be noted that for many European and more northerly American/Canadian enthusiasts, the winters are severe enough that an additional source of warmth is often necessary to keep temperatures in the proper range. Heat pads and ceramic heat emitters (heat lamps often dry out the enclosure excessively and/or cause specimens to hide excessively if the light is not a red bulb; heat rocks should never be used for any invertebrate, or reptile for that matter) are recommended for this purpose, though they should never create hotspots in the enclosure that are greater than the overall ambient temperature, lest the specimens burn themselves while burrowing or walking through that portion of the enclosure. Rheostats connected to the heating components are therefore recommended if the enthusiast is having issues with maintaining a proper temperature.

3. Substrate and Food

The substrate in a millipede enclosure is the most important aspect of millipede care, relatively speaking. It serves as food, a medium to maintain moisture and in which to lay eggs, as a "hide", and so on. As such, it is critical to provide a proper substrate; sadly there still remains much misinformation on what really is a proper substrate online and in literature. Anyone advising to keep specimens on a substrate composed primarily of coco coir, dirt, or a similar product with little to no rotting wood or leaves, and stressing the importance of humidity over soil moisture, does not have experience with raising and breeding millipedes long-term. One very common complaint amongst inexperienced enthusiasts is that their specimens just start randomly dying off, which is most of the time the result of a substrate composed of mostly coco fiber with leaves and wood scattered on the surface.

A proper substrate involves forest material, typically wood and leaves in various stages of decomposition, lichens, mosses, forest humus, etc. Millipedes, being detrivores, need these things (in varying amounts depending on species) in order to survive, and will generally not do well on supplemental foods such as veggies and fruits alone.

There are two major kinds of substrate: food substrate, which is normally a mixture of rotting leaves and rotting wood and serves as the primary source of nutrition, and a base substrate (coco coir, potting soil, forest humus, etc.), which serves as a filler and allows for greater burrowing capability. Quality compost can be seen as a sort of hybrid between the two, providing both rotting material and a good burrowing medium; due to it's variability by region and even pile however, unless one has carefully crafted their own compost pile to create a quality substrate it is often useless. Flake soil mixed with other ingredients such as a small amount of sand has also been used with success by enthusiasts as a sort of hybrid approach to the two types of substrate.

When collecting materials such as wood and leaves, take care to focus one's interests on the appropriate stages of decomposition. Rotting wood that has turned white and flakes/crumbles easily is the best, through brown and tan wood that also flakes and crumbles easily also works well. Logs that are overgrown with rampant molds are best to be avoided (unless one is feeding poly-and-platydesmids, though bracket fungi and polypores generally work best for them). Leaves should be in the stage where they are starting to break apart into smaller pieces; this is usually when they have been on the ground for 3-6 months. Whole leaves that are easily crushed work very well. Leaves that bend easily, are green or freshly fallen, or that have turned black and rotted in anaerobic conditions are best to be avoided; millipedes will not generally eat them, and they will attract unwanted pests such as grain mites and nematodes. Also, be careful to remove other creatures that are living in, on, and around the wood and leaves (the best materials are riddled with other invertebrates, including other millipedes) as best as possible in order to preserve the local environment. In the same vein, do not wantonly destroy habitat or rip apart large logs if you only need a portion of them (it is also recommended to set collected logs outside for a day or two to allow whatever creatures in them to depart; splitting them open also helps with this purpose). It is recommended to spread one's collecting over as wide an area as possible, lest one spot becomes barren.

It is very, very important that the area one collects from has not seen any recent pesticide or chemical applications, and is as free of trash as possible (one contributor found a sock in one of his collection bags after indiscriminately collecting leaves in a less-than-clean area); many enthusiasts have lost specimens due to careless collection of materials. If you cannot collect your own materials, or are tired of receiving unusual glances from passerby, many online sellers offer clean leaves, wood, moss, entire substrate mixes, and even lichens and fungi for decent prices. As always, it is important to check a seller's reputation before purchasing in order to assure the quality of service and the materials.

For round millipedes such as spirostreptids, spirobolids, and julids, along with some of the pill millipedes like glomerids and sphaerotherids, the food substrate should make up at least 50% to 70% of the total volume, followed by the base substrate, which should be about 20% to 40%. Other materials such as mosses, aspen bedding, etc. serve to make the substrate airier and absorb excess moisture when the substrate is moistened (and fill out the 10% on the percentage bar). Every enthusiast who makes their own substrate has a recipe, some that are more successful than others, though all good substrates follow this general scheme. Proper experimentation is key to developing one's own care regimen, and different species often require different substrates. This is especially important to keep in mind when keeping species of different orders together; polydesmids and platydesmids break the above recommended substrate scheme and do best on a substrate that is 90%+ rotting wood (keep in mind many/most platydesmids feed almost strictly on the various fungi that grow on rotting wood).

It is also very important to make sure that rotting wood and rotting leaves one uses for one's substrate are of the proper variety. The vast majority of millipedes do best on the leaves and wood from deciduous hardwood trees such as oaks (Quercus sp.), beeches (Fagus sp.), alders (Alnus sp.), birches (Betula sp.), etc. Softwoods and evergreens, such as pines, cypresses, etc. (Pinus sp., Cupressaceae spp.) can be dangerous to their health due to the sap found in their branches, though a notable exception to this rule are the aspens, cottonwoods, and poplars (Populus sp.). For a select few millipede species, these softwoods should replace hardwoods in the substrate (though these species, such as Onomeris, are rare in culture). Also, Carya sp. (hickory and pecan) and Jugulans sp. (walnut) have natural insecticides in them and have been proven to kill millipedes, and as such are to be avoided despite being hardwoods. Bamboo and rose leaves have been used by some enthusiasts, though they are similar to aspen shavings in being consumed last as the substrate becomes depleted.

In terms of oaks on the United States west coast, Quercus lobata, engelmanii, wislezenii, and douglasii are recommended for collection, as their leaves do not have sharp points like most other Quercus encountered (the coast live oak, agrifolia, is a nightmare in this regard), which while harmless to millipedes, are often very painful to crush with the hands after they have dried, and will sometimes leave their sharp points buried deep in the skin.

In order to avoid the addition of pests to the enclosure, it is important to sterilize, or perhaps more accurately "pasteurize," any and all suspect materials, including collected ones. On this many millipede enthusiasts are not in agreement; some argue that a low-temperature bake in the oven (200°F/93.3°C for 30 minutes up to 250-300°F/121.1°C-148.9°C for 2-4 hours) is sufficient, while others claim freezing for a few days does the trick. Still others utilize boiling and/or microwaving for a period of time, or say simply spreading the materials in full sun for a few hours is all that is necessary. All these methods usually do the job of killing most/all pests (freezing using a conventional kitchen freezer is one method that often fails to kill certain pests such as centipedes, nematodes, and dermapterans). It is recommended however that whatever option one chooses, make sure it does not burn the leaves or wood, and that the temperature is not excessive. Often when an enthusiast "overkills" pasteurization and moves closer to sterilization through using high heat levels and/or excessive amounts of time in the oven/microwave, it eliminates or reduces the fungal and bacterial communities already present, so that when introduced to a moist environment, it acts as a blank canvas for undesirable fungal and bacterial growths. Indeed, one of the most common problems after creating a new setup is rampant mold outbreaks, which can often be traced back to excessive pasteurization techniques. Lastly, unless one uses the boiling method, it is important to make sure the materials are as dry as possible before being pasteurized; if moisture remains inside a log or on the bottom of a pan of leaves after pasteurization there is a good possibility a small pest also survived, no matter the temperature used. Breaking up logs and crushing leaves helps prevent moist pockets from forming.

Alongside the substrate, millipedes often appreciate supplemental foods such as fruits, vegetables, dog/cat/fish/tortoise food, powdered milk, etc. While not altogether necessary, most round millipedes will heartily eat these supplemental foods when offered at intervals. Poly-and-platydesmids will generally not eat any supplemental foods; information is lacking for glomerids and sphaerotherids. Whatever food is chosen, be careful to make sure all supplemental foods are free of pesticides and other chemicals, as well as from potentially harmful pests. Keep in mind also that while a product may be labeled as Organic, this does not mean the product is necessarily safe due to the prevalence of "organic" pesticides (the irony here is that anything containing carbon could be considered organic...). Uneaten food should be removed within a day or two to prevent mold and pest outbreaks as the food decomposes, though this is less of a concern with vegetables such as carrots and many types of squash. Supplemental foods can be offered once a week to once every few months, depending on the enthusiast, the number of specimens, and how rapidly the food is consumed.

Many enthusiasts add calcium additives, ranging in form from reptile calcium powders to crushed egg shells to cuttle bones, to their substrate mixes. While many millipedes will chew on these items, there is no evidence they contribute noticeably to the health or growth of millipedes in captivity.

Arthroverts' Round Millipede Recipe

All collected materials are pasteurized by placing them on pans in the sun for up to 1-2 days and stirring them several times over the same period. All ingredients are then thoroughly mixed together and moistened.

• 30% coco coir OR 30% flake soil. This serves as the base.

• 25-30% rotting leaves. Leaves are best crushed instead of used whole.

• 10-20% crushed rotting wood AND/OR 10-20% flake soil (if not used in lieu of coco coir). White rotting wood that flakes and crumbles easily is the best for this application.

• 10% dried sphagnum moss. This helps absorb excess moisture and creates a more airy substrate.

• 10-15% aspen bedding. This serves the same purpose as the sphagnum moss, but will also decompose and be eaten over time.

A few handfuls of millipede frass if available (this will help offspring and buffer mold outbreaks). Topped off with a layer of rotting leaves and perhaps a few larger pieces/logs of rotting wood half-buried; sticks covered in lichen are added to the surface if available. This substrate is fairly easy to make, and can easily be reduced down to the base substrate, rotting wood, and rotting leaves for a good temporary substrate.

It is important to note that unlike most predatory invertebrates, since the substrate is a millipede's main food source, it will need to be changed or added to with more regularity. If the substrate is close to the point where it is entirely composed of frass, it is time to change it. For many species a thick layer of rotting leaves on the surface of the substrate is also appreciated (and in the case of Archispirostreptus gigas may be necessary for breeding), and should be periodically replenished as the leaves are eaten. "Random" deaths can often occur when the substrate has not been replaced in a long time or is of a poor quality. If there are numerous offspring in the enclosure, or some of the specimens have burrowed away to molt, it may be a better idea to simply add more substrate to the surface of the old substrate, provided the enclosure is high enough. Eventually one will need to replace the entirety of the substrate, in which case it is recommended to remove all specimens from the surface as they appear over the course of a few days, and then go through all the substrate to remove any other specimens (keep in mind some molting specimens may be crushed in doing so). If there are small offspring in the enclosure it is best to set aside the substrate in bags or another bin to see if any more eggs hatch or young appear. If in doubt, this is the best practice. Old substrate can be thrown into the garden or a compost pile after being sterilized (be sure there are no missed millipedes first to avoid cooking/freezing any specimens), or used as an alternative to coco coir/potting soil as the base substrate with the next batch.

4. General Behavior

Round millipedes, as well as the pill/ball millipedes, are in general light-shy, fossorial creatures that will spend much of their time underground. Polydesmids on the other hand tend to be much more surface active, and will rarely burrow for long stretches of time except when molting and laying eggs. The platydesmids, which are often lumped in with polydesmids and called flat millipedes, are more cryptic by nature, and will rarely be seen on the surface en masse. Whatever millipede species one keeps, it is important to avoid digging up specimens when they go underground. This is especially a problem with neophytes, who become anxious as soon as the specimen(s) are no longer easily visible. Remember that millipedes are fossorial in the wild, and burrowing behavior is perfectly normal and to be expected. Millipedes burrow to molt and to lay eggs as well; unearthing them in the case of the former can be deadly (the authors can recount multiple reports of specimens killed due to ill-timed digging), and in the case of the latter eggs can be injured or killed. Should one's specimens go underground, the best thing to do is to wait; if they do not surface within six months, it may be worth gently probing the upper layers of the substrate to see if the specimens have died. Keep in mind there are reports of specimens going underground for over a year before resurfacing, and there is an inherent risk in digging of any kind. If any are found alive, cover them back up and leave them, especially if they have just molted or are about to molt, in which case they will appear dully colored, similar to when snakes go "opaque" before shedding. If they are in the process of molting it is best to leave them exposed to prevent the substrate causing problems. If any are found dead, there is a good chance other specimens have also perished. If dead specimens are found and a proper care regimen is being followed, it is most anyone's guess as to why, though specimens that were bought in poor health or that were very old often tend to die in such a manner, and such losses are not reflective of a keeper's ability.

Most millipedes species will surface sometime after the room lights have gone out to explore the enclosure and feed upon whatever food is on the surface. Night is usually the best time to view them in such cases, and often they will be seen clustered around whatever supplemental food was offered in the daytime. Keep in mind however that unless one is using a red lamp to see them, many species will begin to burrow away once a light comes on. Some species are active during the daytime (notably Chicobolus spinigerus and most polydesmid species), and many species can be seen in the mornings on the surface, either curled up in coils, twisted into odd convolutions to groom themselves (this will look like the millipede is trying to eat its own body oftentimes), or wandering about in search of food. Most species move rather slowly, and will only start to "run" if touched, exposed to light, misted, or otherwise disturbed. If the enclosure is too dry or there is little-to-no food present, some species will surface even in daylight and race around the enclosure in search of an escape; with a proper care regimen this should never happen, but if it is seen check the moisture levels and whether or not the substrate needs to be replaced. Another common behavior when the substrate begins to get too dry is for specimens to sequester themselves at the bottom of the enclosure, where the majority of remaining moisture will be found. If the substrate appears to be dry and specimens have not been observed in sometime, adding water to the enclosure will help ensure no specimens desiccate. Round millipedes will generally never exude their chemical secretions unless disturbed (though some species/locales will never exude their secretions); some species will do so at even the slightest breath of air. Polydesmids on the other hand are capable of poisoning themselves in poorly-ventilated enclosures due to their proclivity to exude their secretions constantly.

While many millipedes will explore new branches, logs, etc. that are added to the enclosure, millipedes are not like many vertebrates (or even invertebrates for that matter) in needing stimulation or "play time". As such handling and providing "toys" is solely for the pleasure of the enthusiast, and provided it is done safely, has no affects on the millipedes. When handling be sure to always keep the specimen(s) no higher than their body length above a surface, and they should always be handled over something to cushion a fall, such as a clean blanket. One should also wash their hands before and after handling, to prevent chemicals and other products from harming the millipede during handling, and to prevent any chemical secretions from the millipede from traveling to sensitive parts of the enthusiast's body, such as the eyes. Some species have powerful secretions that are capable of inflicting painful chemical burns and potentially severely injuring sensitive parts of the body; for these reasons it is advised not to handle millipedes that are secreting, to put specimens on one's face, or to handle specimens that are known to have especially powerful chemical defenses. The exudate of small specimens is generally not harmful (as always keep it away from one's face and other sensitive parts of the body), but it will discolor skin a yellowish-brown for up to several months if it isn't washed off within a minute of it being applied. Rubbing the affected skin on soil or leaves quickly removes the exudate and usually prevents the skin from being discolored if water isn't readily available.

See the species reports on the family pages for specific behavioral information.

5. Cage Mates

Principally all round millipedes can be kept together without issue so long as each species' care requirements are met. Millipedes are not eusocial however, and do not require other specimens to survive or thrive. Keep in mind that for breeding purposes it is often best to leave the males and females of tropical and temperate species together (species that hail from arid regions and so thus require seasonal variation to breed consistently can sometimes be induced to mate if the males are removed from the females for a period of time, and reintroduced at the start of the "monsoon" season).

Sphaerotherids can also be housed with round millipedes, though the cool temperatures preferred by some of the larger species may be at odds with the temperatures needed by the round millipedes. There are very few reports of enthusiasts keeping glomerids and round millipedes together. Flat millipedes (poly-and-platydesmids) usually require a substrate that is mostly crushed rotting wood; they also exude their chemical defenses constantly, and so thus are best kept by themselves. Many species also appreciate cool temperatures that are not favored by other tropical and temperate round species.

Whenever considering housing multiple species together be sure to research and make sure the species one has selected are not capable of hybridizing (the same goes for housing different color forms of distinct locales together). This is usually only a problem with species from the same genus or species complex, but it should be researched and considered whenever housing similarly sized species that are closely related. Many enthusiasts often ask why this is important, to which experienced breeders will answer that it is of utmost importance to safeguard the genetics that make each species unique. This may appear to be a rather esoteric answer, but one only has to look to what has happened with many of the species of hissing roach (Gromphadorhina, Elliptorhina, "Princisia", etc.) from Madagascar in both the North American and European fronts of the hobby that have now been muddled with each other to produce drab-looking hybrids that have lost all of the appeal that made the pure specimens attractive. Any and all enthusiasts/breeders should do their best to prevent the same happening with millipedes. By the same token, different localities of the same species should be kept separately, especially when the taxonomy of the species in question is doubtful, or if there is a possibility that one is keeping a species complex.

Non-millipede cage mates are generally inadvisable. Springtails (various Collembola) are to be welcomed in the enclosure, due to their great work in eating rotting detritus and molds. Sinella curisvesta is the one species that is not recommended to be used with millipedes and indeed most other invertebrates due to their ability to explode in numbers and stress specimens out through constant tactile stimulation (similar to issues that arise when there are grain mite outbreaks). Other such creatures, for example isopods, roaches, slugs, and snails, are to be avoided due to their penchant to disturb or eat molting millipedes, cover their spiracles in slime (a problem with gastropods), or otherwise outcompete them for food. All of the above have been observed to feed on young and molting specimens. With careful planning (and at times experimentation) it is possible to mix certain species of different groups, though if in doubt, keep them separately. Other invertebrates such as phasmids could possibly be kept with millipedes due to their disparate lifestyles, but adequately balancing the care requirements of both is often tricky.

6. Health Problems

While millipedes suffer from less observable health problems than might befall a mammal or avian, there are still a few which are cause for concern on captive animals. One of the most common are damaged segments, dented segments, and scratched exoskeletons. These are usually the result of mismolts or damage received during a molt, and are especially common on wild caught specimens. Generally speaking they are not life-threatening. Over time captive populations can also develop small deformities not seen in wild populations. Note the dented collum on the below Trigoniulus macropygus (image compliments of Kevin Nasser).