Beier's Pill Woodlouse

🔤 Taxonomy

Armadillidium beieri Strouhal, 1937 is the accepted name. Schmalfuss’s redescription measured a maximum of 18.0 mm and confirmed that the species has strongly pointed dorsal tubercles, features that help separate it from smoother Ionian Armadillidium.

No widely useful taxonomic synonym is established. A culture should therefore carry the full species name and supplier locality rather than a newly invented colour name.

📌 Description

Adults reach about 1.4-1.8 cm, with a broad body that closes into a ball. Published specimens are brownish grey; females and juveniles can be paler and may have yellowish lateral plates. The coarse dorsal tubercles are more informative than colour alone.

This is a range-restricted Mediterranean display isopod. Its main captive requirement is not high humidity but access to a cool, moist lower refuge alongside well-aerated, less-wet substrate.

🌍 Distribution

Verified records are limited to the Greek Ionian islands of Lefkada, Kalamos and Kefalonia. Schmalfuss specifically corrected an older report from Zakynthos. The country map is therefore intentionally coarse and must not be read as presence across Greece.

⚖️ Legal status

Checked on 2026-08-29: A. beieri is not listed in the CITES Appendices, EU wildlife-trade Annexes A-D under Regulation (EU) 2026/1383, or Bern Convention Appendices II-III. Absence from those lists does not authorize collection on protected land or export from Greece.

Choose captive-established stock, retain invoices and the complete locality label, and verify collection, transport, import, breeding and sale rules for both origin and destination. Never release animals or live culture substrate outdoors.

🤌 Husbandry

A secure 25 x 18 x 15 cm tub suits a 10-20-animal starter group. Use fine cross-ventilation and place more vent area over the less-wet half. Overlapping leaves and cork should connect the moisture zones so the animals do not have to cross bare ground.

Quarantine new stock for 45-60 days with separate tools. Record losses and births, check for mites or mixed species, and do not merge cultures merely because both arrived under the same name.

💡 Lighting

UVB is unnecessary. Give 10-14 hours of diffuse room or plant light according to season, with permanent shade under cork and leaf litter. Direct sun can overheat a small colony within minutes.

🌡 Heating and temperature

Maintain 18-24°C, with a 16-20°C retreat and nights around 15-20°C. Established colonies can slow naturally in a cool room, but forced winter cooling is unnecessary. Do not deliberately chill juveniles, thin animals or recent imports.

Avoid sustained temperatures above 26°C. If room heat is insufficient, warm only one outer wall under thermostat control; never heat the damp base from below.

💧 Humidity and water

Keep about one-third of the substrate damp through its depth, a transitional middle, and a less-wet surface at the ventilated end. Add water directly to the damp corner rather than spraying the whole enclosure. A nominal 50-70% RH is useful, but substrate choice matters more than one air reading.

No open water dish is needed. Persistent condensation and fungus indicate excess water or weak airflow; failed moults and crowding in the last damp crevice indicate drying.

🌿 Enclosure and decoration

Use 6-8 cm of pesticide-free topsoil, deciduous leaf mould and soft white-rotted hardwood. Cover most of the surface with oak, beech, maple or other safe hardwood leaves. Add cork flats, a little moss at the damp end and a stable piece of cuttlebone or limestone.

Avoid fertilized soil, aromatic conifer wood, fresh manure and a sterile coir-only base. Leaves and decayed wood are both substrate and staple food, so replenish them before the old layer disappears.

🪳 Feeding

Keep decayed hardwood leaves and rotten wood available continuously. Offer small pieces of squash, carrot, mushroom, courgette or sweet potato two or three times weekly. Give a small pinch of dried shrimp, gammarus or quality fish food about once a week.

Remove moist leftovers within 24-48 hours. Protein is supplementary; generous portions commonly create mites and fouled pockets without improving the colony.

🥚 Breeding

The repository uses “viviparous” for marsupial brooders. Eggs and embryos develop inside the female’s ventral brood pouch, and she releases mancae rather than laying exposed eggs.

Breeding is best treated as moderate until the colony contains several age classes. Stable lower-layer moisture, leaf fragments and calcium near the damp refuge support newborns. Do not isolate brooding females.

🩺 Common problems

• Failed moults: restore the damp lower refuge and check calcium and heat.
• No recruitment: reduce disturbance and confirm that fine leaves and restrained protein reach the moist zone.
• Mites or fungus: remove leftovers and increase airflow over the drier half.
• Heat-related losses: cool the room and preserve a damp retreat; heavy misting does not correct overheating.
• Uncertain identity: retain provenance and do not distribute mixed or unverified stock as A. beieri.

📌 Conclusion

Beier’s pill woodlouse suits a keeper who can preserve a cool moisture gradient and careful provenance. The greatest avoidable mistake is treating a narrow-island species as a generic, uniformly damp clean-up crew.

📚 Sources and further reading

• GBIF: Armadillidium beieri
• Schmalfuss 2011: Armadillidium of the Ionian islands
• Schmalfuss 2003: world catalog of terrestrial isopods
• Kight 2008: reproductive ecology of terrestrial isopods
• ReptiFiles — checked; no species-specific care guide was found
• CITES Appendices, valid from 5 March 2026
• Commission Regulation (EU) 2026/1383
• Bern Convention appendices