Tetramorium obtusidens

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to Southeast Asia including Singapore, Brunei, Borneo, Malaysia, Indonesia, the Philippines, southern China, and possibly New Guinea. Lives in lowland dipterocarp forests and deciduous forests, typically on tree trunks or in rotten branches^[4][5][3][6].
• Colony Type: Unconfirmed. There is no published data on the social structure of this species.
• Size & Growth:
  • Queen: Unknown^[1]
  • Worker: 2.4-2.7 mm total length^[1]
  • Colony: Unknown
  • Growth: Unknown
  • Development: Unknown (No direct development data is available for this species.)
• Antkeeping:
  • Temperature: Tropical species, so keep warm around 24-28°C. The exact optimal range is unknown, but this is a reasonable starting point based on its habitat^[4].
  • Humidity: Keep the nest substrate consistently moist but not waterlogged. Use a water source in the outworld. Good ventilation is important to prevent mold. No exact humidity data is available.
  • Diapause: Likely none. As a tropical species, it probably does not need a winter rest, though activity may slow if temperatures drop.
  • Nesting: Use a Y-tong (AAC), plaster, or soil nest with very tight chambers scaled to the tiny 2-3 mm workers. Provide pieces of rotten wood or bark, as they naturally nest in rotten branches^[6]. Escape prevention is critical.
• Behavior: Workers are very small and active. They forage in the canopy in nature and are likely generalist scavengers. Because of their tiny size, escape prevention is critical – they can squeeze through the smallest gaps. They are not aggressive toward keepers but may use a smear defense (smearing venom rather than stinging).
• Common Issues: escape risk is extreme due to 2-2.7 mm size – use the finest mesh and seal all gaps., high humidity needs can cause mold if ventilation is poor, balance moisture and airflow., wild-caught colonies may harbor parasites or pathogens, Quarantine new colonies., colony growth may be very slow because founding behavior and development timeline are unknown., canopy-dwelling lifestyle may lead to stress in ground-level formicaria, provide vertical climbing surfaces.

Housing and Nest Setup

Because workers are only 2.4-2.7 mm, you need a nest with very narrow chambers. Use Y-tong (AAC), plaster, or soil nests designed for small species. Avoid large open spaces – the ants will feel insecure. In the wild they were found inside a rotten branch^[6], so adding pieces of soft wood or bark can make them more comfortable. Your outworld should have tight connections. Escape prevention is the top priority: use the finest mesh (e.g.,0.2 mm) on ventilation holes and seal every crack with silicone or tape. They can walk up smooth vertical surfaces, so cover the outworld walls with a barrier (e.g., fluon) if needed.

Temperature and Heating

Tetramorium obtusidens is a tropical species from lowland forests^[4], so keep your colony warm. Aim for 24-28°C. Use a small heating cable on one side of the nest to create a temperature gradient – the ants will choose where they are comfortable. Prolonged chilling below 22°C may slow or stop brood development. Room temperature within this range is fine if your room stays warm year-round.

Feeding and Diet

No exact diet data exists for this species. Based on its habitat (rotten branches, canopy) and its membership in the bicarinatum group, it is likely a generalist scavenger. Offer small protein sources: fruit flies, tiny mealworm pieces, or springtails. For carbohydrates, use a drop of sugar water (1:4 sugar to water) or honey. Feed a few times per week in small amounts. Remove uneaten food to prevent mold. Ants were found together with other species^[6], but that does not tell us about their diet.

Humidity and Water

Tropical forest species need moisture. Keep the nest substrate damp to the touch – like a squeezed sponge – but never waterlogged. A test tube with a cotton plug or a small drinking bottle connected to the nest provides drinking water and helps maintain humidity. Good air exchange is essential to stop mold from taking over. There is no published humidity range, so watch your ants: if they avoid a dry nest area, they need more moisture. ^[4]

Colony Development and Growth

Absolutely nothing is known about the founding behavior, development time, or colony size of this species. The first workers probably emerge several weeks after egg-laying, but we have no data to give you a timeline. Be patient and observe. Because the queen size is unknown, you cannot even guess at claustral or semi-claustral founding. Treat any ‘estimate’ in other sources as a guess.

Handling and Temperament

Workers are small and not aggressive. They do not sting in the usual sense, instead they have a modified stinger that smears venom. This defense is unlikely to bother you, but it can irritate – avoid getting it in your eyes. When maintaining the nest, use a soft brush and let the ants walk onto tools rather than picking them up. Their tiny size means they are easy to crush accidentally. Always work over a tub or tray to catch escapees.

Frequently Asked Questions

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References