Brachycybe

Found at an elevation of 1480 ft/451 m in extremely rotted pine. Population was very concentrated and I only found them on one rotted pine log, but there were ~30 visible specimens and of those, multiple males were caring for eggs. If I dug a bit deeper there probably would have been even more specimens. Found in Marin County.

Substrate is a pretty loose requirement with Northern Californian Brachycybe, they can utilize a variety of different materials but seem to prefer a thick coating of old, well decomposed leaf litter, coniferous or oak, on top of the substrate. Substrate depth does not matter as long as it is there. The only other thing needed in their enclosures is plenty of wood, decomposed and rotten but not crumbly. I have noticed that in the wild they prefer to congregate on still solid fallen branches or logs. Wood type is another matter, I find they prefer either oak or pine. In the wild this preference seems to depend on altitude, with high altitude populations preferring pine and low altitude populations preferring oak. This could have to do with the species of tree found at their respective altitudes, species of fungus that grows on wood at their altitude, or something else. I have only sampled at three different locations so it is hard to say for sure.

Brachycybe prefer cold conditions with a comfortable amount of humidity to be productive, not enough to condensate profusely but not too little either. The Brachycybe populations I have studied are actually quite resistant to high temperatures and low humidity, with summer temperatures reaching over 100 degrees Fahrenheit (37.7 Celsius) and no natural rainfall for little under half the year. To combat these unfavorable conditions Brachycybe will estivate during the summer months, coiling up and entering a period of inactivity. This is the only time you will see the millipedes coiled up naturally, as they will not do so for defense or any other purpose. Before estivating it is not uncommon for the entire group to molt en masse. This estivation seems to be triggered by a biological clock, but I have not tested whether it can be triggered/hindered artificially. For ventilation very little is needed and indeed they seem to do better when airflow is minimal.

Food wise, they are entirely dependent on fungi. I have seen online that polypores and bracket fungi are supposedly the best food. This is not so, or at least not with cf. rosea/producta. While they will consume polypores and brackets, they do so sparingly and I have had many individuals starve to death even when provided with plenty of both. Preferred food for these two species is a sort of mold, white and very fuzzy, that grows on rotten wood. I am not sure what this mold is but the millipedes seem to be receptive to several different types. One critical part of keeping this mold alive for as long as possible is to spread the inoculated wood in as thin a layer as can be had. Avoid stacking it, as layering too much of it seems to quickly kill the mold. When provided with this mold the millipedes will reproduce very quickly. This is also the only food I have ever seen wild individuals feed on, with certain logs and branches that have a lot of said mold attracting thousands of individuals every year. Unfortunately this mold is very hard to maintain in captivity long term and providing enough of it remains the biggest struggle I have with keeping these millipedes.

When in favorable conditions, the millipedes reproduce very quickly and can triple their population within a few months. I have found it to be very hard supplying their exponentially increasing populations with food, and indeed they often seem to kill themselves when the population becomes too large for the resident mold populations to sustain. Be prepared for a lot of micromanaging and foraging outside when the fungus you already have runs out.

Some miscellaneous notes are included here. These millipedes should not be kept with other large animals, as when disturbed they release a very strong, citrus-smelling liquid from the tips of their segments. This gas is a very potent defense and in enclosed areas quickly kills other arthropods. Springtails and such should also be kept at a minimum, as they can steal fungus food from the ever-needy millipedes. The millipedes themselves seem quite variable in coloration, or at least cf. producta does. Higher altitude populations are a very attractive dark pink instead of the usual yellowish orange, and I have suspicions they are a different species.

The notes provided here are merely a collection of suggestions based on my own experiments. They are not necessarily absolute, and I have reason to believe care varies within the same species depending on the location of collection. Much more time and effort is needed before I can feel comfortable in saying that reliable reproduction and husbandry has been attained.

Below photos of cf. rosea and cf. producta compliments of Ponerinecat (9).

Low altitude cf. producta with juveniles, feeding.

cf. rosea with juveniles, feeding.

cf. rosea.

High altitude cf. producta, feeding.

Group of estivating cf. rosea.

Mass of shed exoskeletons.

Three life stages of low altitude cf. producta.

cf. producta and rosea feeding on a particularly healthy clump of mold.

Food mold.

High altitude producta and rosea in-situ, feeding under the bark of a pine log.

Wild cf. rosea male with eggs. This particular male was underneath a very reliable log that gets thousands of cf. rosea at any one time in the fall months.

My largest adult is 1.5” long and about 1/8”wide.

1. They can climb glass and plastic. So it is best to keep them in a container with a seal. I use open screen vents and insert pipe screens inside those to make sure they can’t make their way through it when they first hatch.

2. Use really soft rotten hardwood. So rotten that you could crumble it with your hands. I crumble some into their substrate (it makes up about 50% of the substrate base). I also leave larger pieces on the surface.

3. Add bark on top of their substrate. They seem to seek out the pieces that are really rotten. They also seem to like drift wood with lots of little grooves in it.

4. Their container needs to have a humidity variant. One end needs to be damp, but not dripping wet. They are prone to foot rot and will not do well if kept too moist.

5. They absolutely love small limbs with polypore fungi on it. This is the most critical part. Polypore fungus will be their primary food source. I have also seen them munching on mold from time to time.

Brachycybe lecontii. Note the male guarding eggs. Photos compliments of Stephanie Risberg (11).