Apheloria

Apheloria is a North American genus of flat-backed millipedes with 25 accepted species, occurring most predominantly along the United States eastern coast, with the most sightings in and east of the Appalachian Mountain range (1).
Theodore H. Eaton, Jr. describes in The American Midland Naturalist the soil habitats in the upper Appalachian range in New York that Apheloria are found in in detail, noting that A. coriacea and what is now Rudiloria trimaculata are mull-creating species (2).
Mull is specifically a type of humus where organic matter is mixed thoroughly with mineral content in the soil. In the deciduous forests that many Apheloria call home, mull is the most common type of humus. Near North Hudson, New York, this mull layer where Apheloria were observed was comprised of clumps of fecal matter from the millipedes, organic matter, dead fungal hyphae, organic detritus, and mineral granules. Apheloria have also been found in natural peat in large numbers, more densely than even in the mull-humus soil areas.

Captive efforts to keep and breed Apheloria spp. have completely failed. Most attempts have not even seen specimens molt or feed, much less breed. Troubleshooting efforts have suggested keeping specimens at cooler temperatures, that is, between 65-72°F/18.3-22.2°C, but lower temperatures have yet to provide positive results.
Recently, research first conducted by Eaton in 1943 has been brought to light that shows that temperature may have very little to do with the problem (2).
Eaton conducted a feeding experiment with Apheloria coriacea (which was later synonomized with Apheloria virginiensis corrugata by Hoffman in 1999 [3]), supplying specimens with clean, dead leaves of basswood, sugar maple, white ash, white oak, and beech that were soaked in water for a minimum of one hour to soften them. These leaves were then given to adults and left for 48 hours, with no feeding or evidence of feeding observed. However, when given fresh peat, more than half of the millipedes were observed eating after only ten minutes. Two adult pairs were removed from the peat and put in a different container containing mull-humus soil with no leaves or other organic material such as wood, and for three weeks were observed to feed freely on the mull. They sparingly ate softened dead bark of white oak when it was offered. The specimens were kept between 24-27°C/75-80°F at all times.
These observations suggest that the loose leaf litter and crumbled rotting wood that is used in standard millipede care as food substrate is insufficient for at least Apheloria virginiensis corrugata, and possibly the rest of the genus. Rather, specimens would do well with ample mull-humus and peat as food substrate.
Though Eaton had no issues keeping large numbers of them alive in a lab setting, he was able to provide readily accepted food sources, something most enthusiasts do not have easy access to. Nevertheless, the data above suggests that if the study can be replicated there is hope for consistently keeping and even breeding Apheloria and possibly other North American Xystodesmidae in captivity.

Members of this genus are blind and exhibit Müllerian mimicry, categorized by aposematic coloration, or in other words, the array of yellows, reds, oranges, and pinks many species bear (4). Though this signals to predators that they are unsuitable as prey visually, individuals also are capable of cyanogenesis, secreting hydrogen cyanide through their ozopores via muscle-controlled valves.
In practicality, this means specimens can poison themselves if kept in unventilated enclosures. Some species have several different color varieties, such as A. polychroma, which is something to be considered when sourcing or potentially collecting specimens (5).

Apheloria montana adult and juvenile (7).

Notes on Apheloria polychroma, by Connor Smotzer

Another species that has entered culture is the most recently described xystodesmid, Apheloria polychroma. It was originally called Apheloria "flavissima" by Richard Hoffman.
The name was changed and elevated officially to species level in 2018 by Marek et al., who assigned the specific epithet polychroma based on its multitude of known color morphs.

Those color morphs are as follows (assignment of letters based on Figure 2 of Marek, Means, & Hennen (2018)):

A. Four-spotted yellow morph with red legs

C. Four-spotted yellow morph with yellow legs

E. Four-spotted orange morph with orange legs and orange collum

G. Striped yellow morph

I. Three-spotted white morph with red legs

K. Three-spotted light-yellow morph with orange/yellow legs

M. Stripped/Four-spotted yellow mixed morph

O. Four-spotted yellow morph with hourglass shape medially on the collum

Q. Two-spotted yellow morph

S. Two-spotted yellow morph with small median spots


Apheloria cf. polychroma, courtesy of Samson Braden.

Observation of Apheloria cf. polychroma breeding behavior, by Connor Smotzer

At 6:00am on October 22nd, 2022 I witnessed a male-female pair of, four-spotted yellow color morph with yellow legs, Apheloria cf. polychroma interlocked in the process of breeding. This was shocking to witness less than 24 hours after receiving them. The behavior was observed when the in-enclosure temperature was 66.6ºF, the ambient room temperature of 67.1ºF, and the ambient room relative humidity of 50%, so the in-enclosure humidity was probably closer to 70-80%.

Individuals were housed in a 54qt tub with about 6" of topsoil/peat/leaf-wood substrate with crumbling rotting white Quercus fusiformis and Acer grandidentatum moss-covered branches covering 50% of the soil surface, with 10% covered by live Sphagnum moss. The rest of the surface was covered with the same tree species' leaves.

Apheloria cf. polychroma in-situ, courtesy of Samson Braden. The color of this individual may appear orange but the collector remarked that it is most likely the white balance and light of the photo as this individual was yellow like in the above photo.

Apheloria cf. polychroma, Courtesy of Connor Smotzer



  1. iNaturalist. (2021). Apheloria. Genus Apheloria Map. https://www.inaturalist.org/taxa/70418-Apheloria

  2. Eaton, T, H, Jr. (1943). Biology of Mull-Forming Millipede, Apheloria coriacea (Koch). The American Midland Naturalist; 29(3), 713-723. https://www.jstor.org/stable/2421158

  3. Hoffman, R, L. (1999). Checklist of the millipedes of North and Middle America. Virginia Museum of Natural History, special publication, 8: 1-584. Martinsville. https://www.fieldmuseum.org/sites/default/files/hoffman_checklist_1999.pdf

  4. Marek, P, E. & Bond, J, E. (2009). A Mullerian mimicry ring in Applalachian millipedes. PNAS. 106(24), 9755-9760. https://www.pnas.org/content/pnas/106/24/9755.full.pdf

  5. Marek, P, E., Means, J, C., & Hennen, D, A. (2018). Apheloria polychroma, a new species of millipede from the Cumberland Mountains (Polydesmida: Xystodesmidae). Zootaxa, 4375(3), 409–425. https://vtechworks.lib.vt.edu/bitstream/handle/10919/86641/Mareketal_ZT_2018.pdf?sequence=2

  6. Sierwald, P.; Spelda, J. (2021). MilliBase. Apheloria Chamberlin, 1921. Accessed at: http://www.millibase.org/aphia.php?p=taxdetails&id=890999 on 2021-11-10

  7. Risberg, S. (2022). Apheloria montana. Photographs 1-3. Permission granted to TMED.

  8. Marek, P, E., Means, C, J., & Hennen, D, A.(2018). Apheloria polychroma, a new species of millipede form the Cumberland Mountains (Polydesmida: Xystodesmidae). Zootaxa, 4375 (3), 409-425. https://doi.org/10.11646/zootaxa.4375.3.7

  9. Braden, S. (2022). Apheloria cf. ploychroma in situ. Photographs 1-2. Permission granted to TMED.

  10. Smotzer, C. (2022). Apheloria cf. polychroma. Photographs 1-3. Permission granted to TMED.