Glomeris

Glomeris is a relatively large family of pill millipedes and one of the most species-diverse in its family, composed of 83 species restricted to Europe and North Africa in distribution. Out of these only a handful in comparison have been kept in captivity, namely G. marginata, pulchra, pustulata, hexasticha, connexa, balcanica, and klugii. In Europe a variety of species have variable phenotypes (Glomeris in general have over 400 described color variations, 2), and can look similar to each other to the point of only being able to be differentiated by analysis with a microscope. Because of this, it is almost sure some specimens cultivated have been misidentified; to create further confusion, older names, such as G. undulata (a taxon that was synonymized under klugii, which itself has over 40 different color variations), continue to float around (3). It is unknown for sure, but it is unlikely that the various members of this genus can hybridize due to how many species can be found sympatrically; currently there are no known scientific records discussing this possibility.

Glomeris in many ways remained a mystery in terms of husbandry to breeders and enthusiasts for many years, with numerous reports of failed attempts to culture members of the genus, often G. marginata, to be found in many forums. In recent years this conundrum has been largely resolved, though due to the relative obscurity of the genus and lack of serious breeding projects no standard care methodology has yet been delineated by anyone except perhaps Orin McMonigle, who claims in 2020 April issue of Invertebrates Magazine that the most important aspect of Glomeris, specifically Glomeris pustulata and pulchra, care is the availability of live moss (4). The specimens eat the small amount of soil created by the rhizoids of the moss, causing the moss to fall apart and decompose. It is unclear if the leaves of the moss are eaten. Other species seem to rely less on moss, but a consistent aspect of Glomeris habitats in the wild is the presence of large amounts of rotting wood, forest humus (highly decomposed leaves), and live mosses, and everyone who has been successful in culturing this genus have consistently incorporated these three elements into their enclosures (5). One interesting facet of this genus's behavior is that it builds molting chambers from frass, similar to many polydesmids.

Glomeris range in color from the black segmented, white-banded G. marginata to the black-with-orange/yellow splotched Glomeris pustulata/pulchra to the tan with brown swirling/splotching klugii, though numerous morphotypes across even a single species make any one characterization of coloration or patterning different. All species generally do not reach beyond 25 mm/0.98".

Breeding report of Glomeris marginata, by Lars Mayer (6)

12 specimens were obtained from a locale in Southwest Germany, and placed in a 5 liter plastic enclosure on a substrate of moist flake soil and rotting leaves; ventilation was limited to a dozen 4-5 mm holes in the lid. Sticks covered in moss and lichen were added every few weeks as available; temperature mirrored that outside, being kept in between 5-25°C/41-77°F. I checked on specimens once a week to once a month, though this species generally spends most of its time hiding in the leaves or substrate. In eight months of culturing this species I had three broods produced, each with about a dozen young produced every time. Eggs are laid in capsules of frass, and young appear to have a very high survival rate as I have not seen any deaths amongst the offspring.

G. marginata is easy to find under moist rotting logs in the wild (at least in Germany), and this is reflected in captivity with this species seeming to prefer very well-rotted flake soil.

Photos of adult and baby Glomeris marginata compliments of Lars Mayer (7).

Glomeris pulchra from Croatia with an unidentified specimen from Germany in the center (8).

Thirty specimens of possibly two different Glomeris sp. found under a log in Germany (9).

  1. GBIF.org, GBIF Glomeris Page. Accessed at: https://www.gbif.org/species/search?rank=SPECIES&highertaxon_key=1021715&status=ACCEPTED on 1-25-2022

  2. Hoess R., Scholl A. (1999). Glomeris undulata Koch and G. conspersa Koch are conspecific. - Enzyme electrophoretic evidence and taxonomical consequences (Diplopoda: Glomeridae). Revue suisse de zoologie, Vol. 106, pp. 643-661, accessed at: https://www.biodiversitylibrary.org/page/41279710#page/129/mode/1up on 1-25-2022

  3. Wesener T., Conrad C. (2016). Local Hotspots of Endemism or Artifacts of Incorrect Taxonomy? The Status of Microendemic Pill Millipede Species of the Genus Glomeris in Northern Italy (Diplopoda, Glomerida). PLOS ONE 11(9): e0162284. Accessed at: https://doi.org/10.1371/journal.pone.0162284 on 1-25-2022

  4. McMonigle O. (2020). "Cracking the Glomerid Code". Invertebrates Magazine.

  5. Marigold. (2017). Glomerida - Diplopoda.de Forum. Accessed at: from https://forum-diplopoda-de.translate.goog/forum/index.php?thread/6954-glomerida/&postID=55803&highlight=glomeris&_x_tr_sch=http&_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp#post55803 on 1-31-2022

  6. Mayer L. (2022). Breeding report of Glomeris marginata. Via Email.

  7. Mayer L. (2022). Glomeris marginata. Photographs 1-2. Permission granted to TMED.

  8. Mayer L. (2022). Glomeris pulchra and unidentified sp. Photograph. Permission granted to TMED.

  9. Mayer L. (2022). Glomeris sp. Photographs 1-2. Permission granted to TMED.

Page image courtesy of Adrìan Purkart