Great finds!
The top photos look to me like immature euryurids, likely Euryurus leachii. Where did you find them? The larger polydesmids are of the family Polydesmidae, I think our native genus, Pseudopolydesmus rather than the non-native Polydesmus. You might consider keeping them separate from the Narceus americanus as this much larger millipede may inadvertently crush molting chambers. My foul-tempered individual has literally banged around the enclosure. :wideyed: I added more substrate as I think in that case there wasn't enough space per millipede. It may not be a problem in your larger enclosure, especially if the wood is soft enough for the polydesmids to burrow into.
Yeah, it isn't the best shot to show the gap, but doing a search for male spirobolids on BugGuide, it was the only photo I found that showed it at all!Do have another picture that shows the same thing? I'm having a hard time seeing it in that one.
Congrats on your finds!
That behavior does sound like mating to me (I've only observed my polydesmids mating, but I've seen photos). If you can take photos clearly showing the legs or even underside of the anterior portion of each of your millipedes, we should be able to sex them and if you do have at least one male, I believe that you will see the difference. 
Congrats on the finds! I'm not sure what the small polydesmids in your first two photos are. I have been studying/collecting something similar over the weekend in the Ozarks. I initially thought they were the paradoxosomatid Oxidus gracilis, the introduced European greenhouse millipede, because they are ridiculously prolific (sometimes hundreds per square yard). But I'm not so sure now because they don't look exactly right and because they're deep in the forest where it would be difficult for an introduced species to reach. They're definitely a paradoxosomatid, as indicated by the dorsal sulci. Thus, the research continues...
Congrats on your finds! Like Erin, I've never bred any of the Spiros, so I can't give any personal insight. From what I've read, though, N. americanus is easy to breed in captivity if given damp, rotted wood. That's usually where I find them breeding in the wild as well.
Glad to see that your millipedes are doing well, Erin! Glad to hear that your Apheloria are mating! Also, congrats on the new Euryurus sp. Those are quickly becoming one of my favorites. According to Shelley, all of the handful of Euryurids live and behave the same way, so they should be fairly straightforward to keep and breed. I'll be glad to help if you have questions!UPDATES ON MY MILLIPEDES:
(covering my new species and those whose husbandry I am in the process of working out)
Abacion texense
This one continues to baffle me by hanging out in the area of dampest substrate. I wetted this area further so there is now a gradient from very moist to dry. In addition to the coir, oak (dust, small pieces, and one larger piece with bark) and small bit of sphagnum moss, I included bits of plants from around here that were specifically mentioned in a paper on Abacion texense: a piece of cactus, some dried juniper and some shreds of a decaying yucca leaf.
Apheloria tigona
I bought five of these beauties from BugsInCyberspace and gave them substrate of oak and hickory (from fine to small pieces) with coir mixed in the base and some larger pieces of wood on top, all of it quite moist. The males showed more interest in mating than the females so, based on observations by @Harlequin of his Polydesmids, I figured the missing element was substrate depth. To bring the depth of one corner up to nearly the top of the Sterilite box base, I used those ash wood shreds sold as animal bedding but boiled them first in the hopes of softening them and starting the breakdown process. I wasn't sure how the millipedes would like it but they seem to LOVE it as they have burrowed in and and have been actively mating both within and outside the burrows!
Eurymerodesmus melacis
I don't know that I've found ideal husbandry conditions yet, but they continue to survive in a moist mixture of hardwoods, mostly oak and mesquite, usually completely burrowed, but occasionally on the surface.
Euryuridae sp., most likely Euryurus leachii
I just received some lovely Euryuridae millipedes from @pannaking22 !
Here are two of them (the green is a bit of dried kale -- high in copper!
Harpaphe sp.
I received a pair of these and now matter what I offered, they would restlessly pace about until I covered the substrate with decaying matter from Douglas Fir (sadly, the male died before this, I believe from a fungal infection). The female seems to still be doing well, sometimes burrowed, often on top of the substrate nibbling on something, but no more pacing about the perimeter.
Orthoporous ornatus
Hopefully doing well in hibernation. It feels like it's been longer than it has since last I've seen them, but I must wait and only maintain soil conditions for... another eight months.
So after a bit of literature research, it seems that McAllister was right - N. americanus is the only giant Spiros found in Arkansas, though the very similar N. annularis is nearby in Missouri. It does indeed seem that this is just a highly unusual color morph of the N. americanus-annularis-complex, which means I should have collected that large female when I had the chance. Looks like I'll be making a trip back to that mountain to see if I can find some breeding stock and start my first giant Spiros culture.
I rather suspect that they are and looking again at the smaller pale polydesmids that @Chris52 has found, I see the transverse groove that is characteristic of Oxidus gracilis. It would be most regrettable if they have invaded the Ozarks to such magnitude, a region with so many beautiful native millipedes.
Actually, I think that it does look like N. americanus-annularis -- note the characteristic red legs -- and as you said, it is the only large spirobolid in Arkansas. It is a cool color morph and if it is well-established, I do hope that you'll collect a few more for breeding!
Lovely photo!
Speaking of Pseudopolydesmids, I'm thrilled to see that you have hatchlings! No, no chance of it being E. leachii; I poured over photos and made inquiries and I swear, they are IDENTICAL to A. evides. The other species of Euryurus and Auturus I have not found pictures of.In addition to these, I also found what I believe to be a different Euryurid, but I don't have a photo yet. They are similar to the the Auturus I have, but their legs/antennae are much more brightly colored, appearing to be a bright yellow. I'm color blind, so I'm not sure about the hue, but I know that when beside my Auturus, they are clearly different. This presents yet another mystery because according to McAllister, there are only 2 Euryurids in Arkansas, A. evides and A. louisianus. According to him, the ranges for these two species are divided by the Arkansas River, with A. evides to the north and A. louisianus to the south. But both of the species I now have were from far north of the river and only one county apart from each other. Again, I'll have to cross check with Hoffman's checklist to be sure, but there's a chance that one of the species is E. leachii and the other is A. evides. But I'll have to do further research to know. Incidentally, I'm starting to lose confidence in McAllister.
In any case, I would LOVE to see the ones you've collected! Perhaps A. louisianus has spread since your reference was written?I love Eurymerodesmids, in part because they were the first colorful millipede that I found for myself!
I'd love to see photos of your new species! I'm sorry to hear you had to disband your first culture. It does seem likely that the female had reached the end of her lifespan. Hopefully you'll be able to find more of the others, perhaps after you have your Ozark culture established.I'm still learning my beetles too, but it really does look like one of the scarab dung beetles. We have TONS of Phyllophaga cribrosa around here.
While examining my N. americanus, two of them appear to be missing a pair of legs around the 7th or 8th segment. I don't know if it is a coincidence of not, but with both the ones that are missing the legs, the segment that is missing the pair bulges on top. A third one was not missing andy legs and did not bulge. A fourth would not uncurl so I couldn't check, and my fifth is a juvie, can you tell when their young? Back to the bulging, this is what they look like (sorry for the terrible pic)Yeah, it isn't the best shot to show the gap, but doing a search for male spirobolids on BugGuide, it was the only photo I found that showed it at all!
Congrats on your finds!
Yep, the missing legs combined with the bulge definitely means they are male -- congrats!
That bulge is only present in males. Here are my pair of Chicobolus spinigerus (the female is on the left, the male on the right, heads at the bottom):
Very helpful. Thanks.Yep, the missing legs combined with the bulge definitely means they are male -- congrats!
View attachment 212097
You can see the male's 6th black band (not counting the head) is significantly thicker than those around it while the female's are uniform after the initial narrower bands.
I think that juveniles are more difficult to sex but I'm not sure at what stage they can be. Surely the males would be missing legs even if their gonopods and segment bulge hadn't developed yetl
Thanks! That's very helpful!Yep, the missing legs combined with the bulge definitely means they are male -- congrats!
View attachment 212097
You can see the male's 6th black band (not counting the head) is significantly thicker than those around it while the female's are uniform after the initial narrower bands. No females have this bulge.
I think that juveniles are more difficult to sex but I'm not sure at what stage they can be. Surely the males would be missing legs even if their gonopods and segment bulge hadn't developed yet.
Well, the reason I say that I'm not sure if they're Oxidus gracilis is because most paradoxosomatids have that groove, and since that's a *huge* family of millipedes, it could be any number of them, some of which are native. At least as far as the Ozark population, there are indications both ways. The section of forest where they're most abundant is near the White River, which has been used for barge traffic for over 2 centuries, and I've noted that rivers with barge traffic often have alien populations from stowaways in cargo. That's not so much the case these days with USDA regulations and all, but transport systems that were in operation before those regs are often at fault for introducing alien species. On the other hand, these paradoxosomatids in the Ozarks fill a critical niche in the ecosystem as the primary decomposers of forest litter. There are only a couple of native isopods that only occur in localized 'hotspots' in the forest, so the remainder of the forest would be left without a primary decomposer if it weren't for these paradoxosomatids. That indicates that they're a native, unless of course they displaced the native decomposer and filled the niche, which is possible since they could have had 2 centuries to do so. As I said before, it's very difficult to tell when I'm not a taxonomist.I rather suspect that they are and looking again at the smaller pale polydesmids that @Chris52 has found, I see the transverse groove that is characteristic of Oxidus gracilis. It would be most regrettable if they have invaded the Ozarks to such magnitude, a region with so many beautiful native millipedes.
Yes, especially now since I've seen @Lucanus95 's color morph, I'm convinced this is just another morph. I didn't realize how varied the coloration and patterns of N. americanus-annularis-complex could be, and it's cool to think about the possibilities of what's out there (or could be bred). It's unfortunate that they have such a slow growth rate and reproduction rate. It would take years to build up a good population of a particular morph or cross in captivity without a large initial stock. I'm certainly going to try it, though!Actually, I think that it does look like N. americanus-annularis -- note the characteristic red legs -- and as you said, it is the only large spirobolid in Arkansas. It is a cool color morph and if it is well-established, I do hope that you'll collect a few more for breeding!
I'll try to get some pictures soon. I'm in the process of trying to isolate a mite infestation in my millipedes and trying to keep them from getting into my isopods and springtails while eradicating them from the millipedes. It's really irritating when I had a mite-free setup, and I get infected from an apple I bought at the grocery store.No, no chance of it being E. leachii; I poured over photos and made inquiries and I swear, they are IDENTICAL to A. evides. The other species of Euryurus and Auturus I have not found pictures of.
This past weekend, I made quite a surprising observation among the wild polydesmids in the Ozarks. There were *a lot* of dead ones on the forest floor, even of various sizes/ages. It seems that even in nature, they have a tendency to die off. So far in my millipede project, I've lost an Abacion, a Eurymerodesmid, and two Pseudopolydesmids, all with seemingly no cause. Making that observation in the forest kind of gave me a bit of peace in realizing that it may not be anything I did, but rather just natural process. Losing a large, long-lived millipede like a Narceus would indicate a problem, just as losing large numbers of polydesmids at a time. But it seems that losing one here and there is just to be expected with these little dudes.
I'm new to spiros, but in polydesmids, young males do indeed have the missing legs, though the gonopods are undeveloped. This combined with the fact that most juveniles are small makes it extremely difficult to identify a male juvenile polydesmid without some good magnification, such as a loupe or a stereo microscope. Then getting them to cooperate is yet another matter...
Great find! Those are a very nice color morph! It's amazing how much variety can be found in this species complex.
I looked at some of your previous photos of A. evides and they all appear to have light antennae. Do all of your original population have darker antennae relative to the ones that you found? Based on what knowledge I have, I would say that those you recently found, north of the Arkansas River and with light antennae are definitely A. evides and I believe that all photos I have seen of both A. evides and E. leachii have light antennae (I did a bit of scrutinizing in the hopes of finding any visible difference between those two!) Perhaps the individuals that you originally found with darker antennae are A. louisianus? I am now curious to look for a visual a description in the scientific literature; I could find no pictures of this species.
Yes, part of the problem I have with A. louisianus is that I haven't been able to find any photos or visual descriptions, either, so I have to go entirely by location and range. (Incidentally, that's also why I'm having trouble with our dozen species of Eurymerodesmids. Only about 2 or 3 of them have been photographed, at least as far as what I've found.) But I still think these came from too deep into A. evides range to possibly be A. louisianus, according to comments on the exclusiveness of the ranges from both McAllister and Shelley. This map (from McAllister's pub) shows the ranges of both, with the overlaid red X's showing the approximate locations where I found them.
Yeah, that is really frustrating.
I would LIKE to have photographs of as many of these species as possible for my book, even if they look identical, just because there doesn't seem to be any anywhere. Does one X mark your recent find and the other your latest? It does seem likely that they are all A. evides, although you can see on that map that both species were beginning to migrate into each others range... in 2002? Where did you find that distribution map?Intriguing! Do you have more photos from when they were mating? (I really cannot see their antennae in the one that you uploaded.) I believe that you are correct that increasing the moisture levels stimulated them to mate, but could it be that it did so by first stimulating them to reach a final level of maturity? I find it curious that, as far as I can see, ALL of the photos on BugGuide.net of A. evides have light antennae. To me, this suggests that either they do not live long after reaching this final stage of maturity and reproducing or they are not A. evides after all, but that A. louisianus has migrated further north (and also further assumes that they and not A. evides have dark antennae upon maturity).
