Strumigenys lewisi

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Native to Japan, Korea, China, Taiwan, and Vietnam. Found in both closed and open broadleaf forests at elevations up to 1 180 m ^[4]. Nests under stones, logs, in soil, decayed stumps, or bamboo stems ^[2]. It is also established as an introduced species in Hawaii, Niue, and Malta ^[5][6][7].
• Colony Type: Polygynous, colonies routinely contain multiple queens ^[1][8]. Colony size is small, usually tens to 100 workers, but up to 239 individuals have been recorded ^[2][8].
• Size & Growth:
  • Queen: Size data unavailable (no total length reported in the research).
  • Worker: 2.6-2.7 mm total length ^[1].
  • Colony: Up to 239 workers ^[8].
  • Growth: Slow to moderate
  • Development: Unknown, no specific data available. Based on typical small Strumigenys colonies, expect several months. (Development likely depends on temperature and food availability. Larval stages have not been studied in detail for this species.)
• Antkeeping:
  • Temperature: Keep at room temperature, roughly 20-24 °C. Avoid prolonged exposure above 28 °C. These ants come from temperate forests and prefer moderate temperatures.
  • Humidity: High humidity is essential. Keep the nest substrate consistently moist but not waterlogged. The species lives in forest‑floor leaf litter and soil, so it is sensitive to drying out.
  • Diapause: Yes, this temperate species likely requires a winter rest period. Reduce temperature to 10-15 °C for 2-3 months during winter, though the exact duration has not been confirmed in literature.
  • Nesting: Soil‑based setups are best. Y‑tong, plaster, or 3D‑printed nests with a moist soil substrate work well. Provide leaf litter, wood pieces, or stones for cover. Avoid dry acrylic nests, the ants need high humidity.
• Behavior: 170° while waiting for prey ^[3]. Due to their tiny size (~2 mm), escape prevention is critical, use fine mesh (0.5 mm or smaller) on all openings. In northern populations, queens may have reduced wings and flight ability ^[1].
• Common Issues: tiny size (2 mm) makes escapes likely without fine mesh barriers (, obligate springtail predators, they cannot survive on sugar or general insect prey., small colony size and slow growth can frustrate keepers expecting large, active colonies., sensitive to drying out, must maintain consistently moist substrate., rarely available from ant suppliers, observation is limited to specialists.

Housing and Nest Setup

Strumigenys lewisi thrives in soil‑based setups. A test tube with a water reservoir and a plug of moist soil works for founding colonies. For established colonies, use a naturalistic formicarium with a soil layer 2-3 cm deep, Y‑tong, or plaster nest with a soil chamber. Keep the substrate consistently moist, these ants come from damp forest floor habitat. Add small stones, pieces of bark, or leaf litter to provide cover. Because they are only ~2 mm long, seal all openings with fine mesh ( ^[2][1]

Feeding and Diet

This species is an obligate predator on springtails (Collembola) ^[2][9][3]. It will not accept sugar water, honey, or other insects, you must provide live springtails. Culture your own springtails in a separate container (e.g., a plastic box with charcoal and water) to ensure a constant supply. Offer 2-3 springtails per worker every few days. Remove uneaten prey after 24 hours to prevent mold. The ants are highly specialized and will ignore alternative prey.

Temperature and Seasonal Care

Keep the colony at room temperature, ideally 20-24 °C. Avoid prolonged heat above 28 °C, these ants come from temperate forests and are not heat‑tolerant. During winter, they benefit from a diapause period. Reduce temperature to about 10-15 °C for 2-3 months, although the exact duration has not been determined in research. Monitor for stress signs such as clustering away from heated areas. ^[2][1]

Behavior and Temperament

170° while waiting for a springtail to pass, then snap shut ^[3]. They rarely sting and are harmless to humans. Colonies are polygynous, so multiple queens can coexist peacefully. Workers are tiny (~2 mm) and quick, so they can slip through very small gaps, use fine mesh barriers. In northern populations, queens may have reduced wings and flight ability, making colony foundation even more dependent on existing workers ^[1].

Colony Structure and Reproduction

The species is predominantly polygynous, with multiple queens found in most colonies ^[1][8]. Colony size is small: typically tens to 100 workers, though one study recorded up to 239 individuals ^[2][8]. Winged reproductives (alates) appear in August ^[2]. Northern populations show degenerated flight ability: queens have smaller eyes, reduced ocelli, and narrower fore wings ^[1]. This suggests that new colonies may rely on budding (fission) rather than long‑distance mating flights in cooler regions.

Frequently Asked Questions

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References