Xystocheir dissecta

[Lufox]

After a couple months of putting it off I finally got around to collecting a group of Xystocheir dissecta for a breeding project. Subspecies hasn't been confirmed, but almost certainly Xystocheir dissecta subsp. dissecta. I hope to finally be able to see some success with this genus, I know someone who bred the alpine Xystocheir brachymacris so I hope to have success with this sea level species. These things are wildly fluorescent under UV light and can be easily found using UV at night. Supposedly after rain is better, but I haven't looked for them in the dry months so I can't comment but it would make sense.

I'm using the formula that worked for Motyxia and Xystocheir brachymacris, which is substrate harvested from the point of collection and also redwood duff. Given these are found almost exclusively in redwood groves their substrate is a mixture of heavily decomposed duff (and added calcium) with more lightly decomposed stuff topping it off with branches and other harder materials scattered throughout. I put a few chunks of wood in it as well. I added a few pieces of moss also, not necessarily because moss is found in the groves but rather for hydration purposes. After all, moss is found surrounding the groves so it's not like they're never exposed to it in nature.


These things are super tiny! Close to but definitely shorter then Harpaphe haydeniana.



Definitely some variation among individuals with the intensity of the dorsal stripe changing as well as the brightness+shade of the coloration on the segments. Some seem to have reduced pattern. This could be chalked up to maturity so we'll see what happens over time as the group ages.


All millipedes in the family Xystodesmidae lack eyes. Just a neat feature. I have observed that often these won't react when I open their bins, presumably due to the lack of sensory input due to not seeing the light change. With cylindricals a lack of reaction would often indicate a lethargic specimen which can be good or bad, but with these it's harder to tell.

These last two videos show how fluorescent they are, as well as what the setup looks like. Hopefully with some time and a bit of luck we'll see some babies!
View attachment IMG_2182.mp4
View attachment IMG_2183 (1).mp4

 

[Lufox]

One week in, I had to do a complete substrate change to improve it- there wasn’t enough flake stage decomposed redwood in the first setup. Only two had died and we had a heat wave meaning this species can tolerate high 60s low 70s. Once again, proving that temperature isn’t nearly as important as we had thought with flat backed species.

On another note I noticed them swarming one two lighter colored individuals. If anything this seemed like breeding behavior, but to my knowledge this species doesn’t have sexual dimorphism. I’ll have to observe this further. At the very least this shows they have energy so presumably they are accepting the substrate I provided.

Here’s some more pics of them in the meantime:

 

[Lordosteous]

Any updates on this species?

 

[gzophia]

I'm a bit late to this, but I just wanted to add my two cents.

These guys (Xystocheir dissecta) are all over the place where I live. I was always scared of them as a kid because they looked unlike any kind of millipede I had previously seen and would leave creepy shells after they passed on. To top things off, they also smelled bad (cyanide gas, cough cough...)
My backyard is virtually a barren, muddy, and rocky wasteland with patches of mulch. However, these guys apparently love it, because they're al over the place.

I tried to keep them for a bit, but I didn't really have any success as they weren't eating. I released them into the wild after a short observation period.
They were defecating a lot though, so maybe they were consuming something, just not what I was feeding them.

I don't remember the specifics as I was really young back then, but I do know that they like most kinds of decomposing matter/wood. They also need very high humidity, as they dry out really easily.

 

[JBUSN1990]

I'm a bit late to this, but I just wanted to add my two cents.

These guys (Xystocheir dissecta) are all over the place where I live. I was always scared of them as a kid because they looked unlike any kind of millipede I had previously seen and would leave creepy shells after they passed on. To top things off, they also smelled bad (cyanide gas, cough cough...)
My backyard is virtually a barren, muddy, and rocky wasteland with patches of mulch. However, these guys apparently love it, because they're al over the place.

I tried to keep them for a bit, but I didn't really have any success as they weren't eating. I released them into the wild after a short observation period.
They were defecating a lot though, so maybe they were consuming something, just not what I was feeding them.

I don't remember the specifics as I was really young back then, but I do know that they like most kinds of decomposing matter/wood. They also need very high humidity, as they dry out really easily.

A few small additions, I hope you'll forgive my late arrival: xystodesmidae feed on highly decomposed humus, and they are at the end of the humus decomposition chain. In other words, they eat soil. Although in the wild they are found in leaf litter and under dead wood like other millipedes, their purpose is different from that of other millipedes. Other millipedes come to eat litter, but they come to eat soil. As a result, they can survive very well in some seemingly very infertile places. In captivity, some species can eat a mixture of peat and earthworm/millipede castings (which is strange enough), but many more species seem to have other feeding problems, and some species have been shown to need to hibernate to promote growth.

 

[gzophia]

A few small additions, I hope you'll forgive my late arrival: xystodesmidae feed on highly decomposed humus, and they are at the end of the humus decomposition chain. In other words, they eat soil. Although in the wild they are found in leaf litter and under dead wood like other millipedes, their purpose is different from that of other millipedes. Other millipedes come to eat litter, but they come to eat soil. As a result, they can survive very well in some seemingly very infertile places. In captivity, some species can eat a mixture of peat and earthworm/millipede castings (which is strange enough), but many more species seem to have other feeding problems, and some species have been shown to need to hibernate to promote growth.

No worries at all, this is brilliant! That's so interesting how they essentially eat soil; it does explain how they can be found in some very infertile places (like the barren, muddy half of my yard).
I'll keep all of this in mind in the future; next winter I might take some in for a month or two before releasing them to study these enigmatic millipedes a bit.

I also wrote a long post with some of my personal notes; hope this is relevant as I don't want to copy everything onto this comment:

Xystocheir sp. Husbandry/Natural History Info?

Hello everyone, I live in an area where Xystocheir dissecta is extremely common. In late winter/early spring, you can find them by the dozens at night with a UV light. In fact, on Valentine's Day two months ago, I was in my own front yard looking for bugs and I found 50-100 specimens with a UV...

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