Temnothorax barrettoi

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Tai Po Kau Headland, Hong Kong, lowland coastal woodland at 70 m elevation ^[1]. Also recorded in Thailand (dry evergreen forest, nesting in dead twigs on the forest floor) and Hainan Province, China ^[2][3].
• Colony Type: Social structure unclear. Likely monogyne with ergatoid replacement queens, but the presence of multiple ergatoids in one colony could indicate polygyny ^[3]. More research is needed.
• Size & Growth:
  • Queen: ~1.9 mm (ergatoid queen total length) ^[3]. Winged queens have not been collected.
  • Worker: 2.2 mm ^[1].
  • Colony: Up to 8 workers recorded in the field, based on typical Temnothorax colonies, likely up to 200 workers ^[3].
  • Growth: Moderate
  • Development: Estimated 6-10 weeks at 24-26°C, inferred from related species (No specific data for T. barrettoi, estimate is from other small Temnothorax.)
• Antkeeping:
  • Temperature: Keep at 22-26°C. This subtropical ant prefers steady warmth. Provide a gradient so ants can self‑regulate ^[3].
  • Humidity: Moderate to high. Keep nest substrate slightly moist (not wet). Leaf‑litter species need damp conditions. A moisture gradient is ideal ^[1][3].
  • Diapause: Unlikely to be required. As a subtropical species, it has no strong seasonal cues. A slight cool period (18-20°C) in winter may be beneficial but is not necessary.
  • Nesting: Use small test tubes for founding, then Y‑tong (AAC) nests with narrow chambers. In nature they nest in dead twigs on the forest floor ^[3]. Avoid large open spaces.
• Behavior: Shy and non‑aggressive. Workers are active foragers but flee rather than fight. Tiny size (2.2 mm) means they can slip through most barriers, use fine mesh or fluon. They have a stinger used for venom smearing (typical of Crematogastrini), but almost never strike keepers.
• Common Issues: escapes through tiny gaps, use fine mesh (0.5 mm or smaller), newly described species, care is experimental, little husbandry data, wild‑caught colonies may carry mites or other parasites, overwatering leads to mold, check for condensation and reduce if needed, removing dead workers from nest is normal, but a sudden die‑off often means drying out or overheating

Housing and Nest Setup

Because Temnothorax barrettoi is so tiny (2.2 mm), you must scale your setup accordingly. Y‑tong (AAC) nests with narrow chambers work well, they mimic the small twig cavities these ants naturally nest in ^[3]. Alternatively, small test tubes with a cotton ball water reservoir are perfect for founding colonies. Avoid large, open spaces that would make the ants feel exposed. Cover any ventilation holes or connections with fine mesh (0.5 mm gaps) to prevent escapes, these ants can slip through ordinary barrier materials. For the outworld, use a small plastic container with a tight lid. Add a shallow water dish and tiny food items. During the first months, keep the test tube or formicarium attached directly to the outworld so the ants can move freely.

Feeding and Diet

Like most Temnothorax, T. barrettoi likely accepts small insects, honeydew, and sugar water. In captivity, offer live prey no bigger than the workers themselves, for example, fruit flies, pinhead crickets, or pieces of small mealworms. Provide a drop of honey or sugar water twice a week. Protein is essential for the queen to lay eggs and for the brood to develop. For a founding colony, a tiny piece of cricket or a dead fruit fly will do. Remove any uneaten prey after 24 hours to prevent mould. Once you have workers, offer food on a small dish or directly in the outworld. Keep a constant sugar source available, but change it regularly. ^[3]

Temperature and Seasonal Care

As a subtropical species from Hong Kong and Thailand, T. barrettoi prefers warm, stable conditions, roughly 22-26°C ^[3]. Room temperature usually works, but you may need a small heating mat on one side of the nest during cooler months. The ants will move to their preferred spot. Unlike temperate ants that need a cold hibernation, this species likely does not require diapause. A minor drop to 18-20°C in winter may simulate natural seasonal change and help synchronise colony rhythms, but it is not essential. Keep the temperature above 15°C and below 30°C. Use a digital thermometer to check.

Humidity and Water

Temnothorax barrettoi lives in leaf litter in damp forests ^[1]. In captivity, keep the nesting area moist but not waterlogged. For a test tube setup, the cotton plug should feel wet to the touch but you should see no free water. For Y‑tong nests, moisten one section and let it dry out before rewetting, this creates a gradient they can choose from. Mold is a common problem with high humidity, if you see fuzzy growth, reduce moisture and clean the affected area. A shallow water dish in the outworld gives the ants extra access to water and helps regulate overall humidity.

Ergatoid Queens and Colony Structure

One of the most unusual features of this species is its ergatoid (wingless) queen system. In a Thai colony, researchers found 4 ergatoid queens living alongside 8 workers ^[3]. Ergatoids are born without wings and act as replacement reproductives, if the primary queen dies, an ergatoid can take over. The presence of multiple ergatoids in one colony raises the possibility that T. barrettoi can be polygynous (more than one queen regularly), but this has not been confirmed. Do not try to combine unrelated queens, there is no data on how they react. If you receive a colony with an ergatoid, treat it like a normal queen, she will need food and workers will care for her.

Handling and Observation

These ants are shy and will bolt rather than confront you. They are best observed from a distance. Use a magnifying glass or macro camera lens to appreciate the detailed areolate‑rugose sculpture on their head ^[1]. Minimise disturbances, especially during colony founding. If you need to move the nest, do it gently and give the ants a day to settle. Their small size means they dry out quickly if exposed to air, so keep handling to a bare minimum and always maintain high humidity in the nest. Do not attempt to pick up individual ants, they are too fragile.

Frequently Asked Questions

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References