Strumigenys circothrix

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Japan (Ryukyu Islands), broadleaf forest floor and forest margins, nesting in soil ^[1]
• Colony Type: Unknown, colony structure has not been documented in published research
• Size & Growth:
  • Queen: 1.4mm ^[1]
  • Worker: 1.0-1.2mm ^[1]
  • Colony: Unknown, no published data on colony sizes
  • Growth: Unknown
  • Development: Unknown, no published data on development times (Development likely slow due to their small size, but this is unconfirmed)
• Antkeeping:
  • Temperature: Based on their forest floor origin, keep around 20-24°C. Avoid overheating ^[1]
  • Humidity: High humidity needed to mimic damp forest floor. Keep substrate consistently moist but not waterlogged
  • Diapause: Unknown, they come from a temperate region but diapause requirements have not been studied. Provide a cool resting period (around 10-15°C for 2-3 months) only if you observe winter slowing, otherwise, maintain stable conditions year-round.
  • Nesting: Soil-nesting species. Use moist, fine-grained soil in a shallow container with small chambers ^[1]
• Behavior: Extremely cryptic and docile. These ants avoid confrontation and move slowly. Escape prevention is critical, they can fit through gaps as small as 0.1mm. Use fine mesh (0.5mm or smaller) and tight seals. They are not defensive and cannot sting.
• Common Issues: escape prevention is the top concern, at 1mm, they fit through nearly any gap, wild-caught colonies may carry parasites that kill them in captivity, overheating or drying out will kill them quickly, stress from frequent disturbance can cause colony failure

Housing and Nest Setup

These ants nest in soil, so a naturalistic setup with moist, fine-grained soil works best. Use a small container with 1-2cm of soil that you keep damp but not flooded. A small plaster or Y-tong nest with tiny chambers (2-3mm wide) also works. Since standard test tubes are too large, consider using small plastic containers or modifying a test tube with a narrow entrance. Keep the nest in a dark, low-light area. A water reservoir connected to the nest helps maintain moisture over time ^[1].

Feeding and Diet

The natural diet of Strumigenys circothrix is not documented, but related Strumigenys species are specialized predators of springtails and other micro-arthropods. Based on that, offer live springtails as a staple. You can also try tiny fruit flies or booklice. They likely reject sugar water and larger prey. Feed small amounts every few days and remove leftovers to prevent mold. If they do not accept these foods, experiment with other tiny live prey (e.g., microworms). Their exact dietary needs are unknown, so observe closely.

Temperature and Seasonal Care

Keep the nest area around 20-24°C. These ants come from a temperate climate and do not need high heat. Avoid direct sunlight or heat sources. Since their diapause requirements are unknown, observe their activity in winter. If they slow down, you can gradually reduce temperature to 10-15°C for 2-3 months as a precaution. If they remain active, keep conditions stable. Do not force hibernation if they are still foraging ^[1].

Escape Prevention

This is the most important part of keeping this species. Workers are only 1.0-1.2mm and can squeeze through any gap you might not notice. Use fine mesh (0.5mm or smaller) on ventilation holes. Apply Fluon or PTFE to the rim of containers. Seal all connections with tape or silicone. Check daily for gaps, especially around tubing or access points. Even a small crack can allow the entire colony to escape ^[1].

Handling and Observation

These ants are very docile and do not sting. They spend most of their time hidden in the soil or nest. Observe them with a red filter or in dim light to avoid disturbing them. Do not handle them directly, they are fragile and easily crushed. If you need to move them, use a gentle aspirator or a soft brush. Avoid frequent nest disturbance, as stress can cause colony decline.

Frequently Asked Questions

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References