Polyrhachis maliau

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Endemic to Borneo (Maliau Basin, Sabah, and also in Malaysia) at around 700 m elevation, along creek margins in low vegetation ^[1][2].
• Colony Type: Unknown, no sexual castes have been described ^[1][3]. Colony structure (monogyne, polygyne, etc.) is not documented.
• Size & Growth:
  • Queen: Unknown, not described ^[1][3]
  • Worker: 9.17-9.93 mm total length ^[1]
  • Colony: Unknown, no data on maximum colony size
  • Growth: Unknown, no data available for this species
  • Development: Unknown, not studied. Related Polyrhachis may develop in 6-8 weeks, but this is speculative. (Development time is unconfirmed. Temperature, humidity, and other factors are unknown.)
• Antkeeping:
  • Temperature: Unknown, but inferred from tropical habitat: keep warm (likely 24-28°C). Avoid drops below 20°C. Provide a gradient if possible ^[1].
  • Humidity: Inferred from rainforest habitat: high humidity (substrate consistently moist, but not waterlogged). Provide good ventilation to prevent mold.
  • Diapause: No diapause needed, as a tropical species from equatorial Borneo, they do not experience cold winters.
  • Nesting: Unknown, workers were foraging on low vegetation, so a semi‑arboreal setup with climbing structures may be suitable. Since no nest records exist, experiment with Y‑tong, cork, or soil nests, and adjust based on colony behavior.
• Behavior: Behavior is poorly documented. As a Formicinae, they spray formic acid for defense and lack a functional sting. Workers were found foraging during the day. They are likely not aggressive, but may raise their spines when disturbed. Workers are large enough to be contained with standard barriers like fluon.
• Common Issues: high humidity requirements, mold can develop if ventilation is poor, cold sensitivity, avoid drafts and temperatures below 20°C, unknown founding biology, queen raising may be difficult without established protocols, limited keeper experience, this species is newly described and captive care has not been studied

Housing and Nest Setup

Because the natural nest of Polyrhachis maliau has never been observed, base your setup on their foraging behavior. They were seen on low vegetation, so provide climbing structures like twigs, cork bark, or mesh. A Y‑tong, plaster, or 3D‑printed nest with narrow chambers can work, but you may also try a naturalistic setup with soil and rotting wood. Keep the nest area humid and well‑ventilated. The outworld can be drier. Always provide a water source. ^[1]

Feeding and Nutrition

Workers were observed foraging on vegetation, so they likely eat small insects and honeydew. In captivity, offer a varied diet: small live or pre‑killed insects (fruit flies, small crickets, mealworms) for protein, and sugar water, honey, or diluted syrup for carbohydrates. Feed protein 2-3 times per week and keep sugar available continuously. Remove uneaten prey to avoid mold. Adjust portions based on consumption. ^[1]

Temperature and Seasonal Care

As a tropical species from Borneo, Polyrhachis maliau requires warm conditions year‑round. Aim for 24-28°C in the nest area. Use a heating cable on one side to create a gradient. Room temperature (24-26°C) may be sufficient if your home is warm. Avoid temperatures below 20°C. They do not need diapause (hibernation). If you notice reduced activity during the local dry season, you can slightly lower the temperature by 2-3°C for a few weeks, but this is not necessary and not studied. ^[1]

Behavior and Colony Dynamics

Very little is known about colony dynamics. Workers are diurnal foragers, and their spines probably deter predators. They defend themselves by spraying formic acid (typical of Formicinae) rather than stinging. They are likely not overly aggressive. Because sexuals have never been collected, colony growth and queen behavior are complete unknowns. Keepers should document their observations to help fill this gap. ^[1][3]

Handling and Observation

Workers are about 9.5 mm long and easy to see. They are not known to be aggressive, but like all ants, they may spray formic acid if handled roughly. Use gentle handling and avoid squeezing. They can climb smooth surfaces, so take care with barriers. A magnifying lens reveals the fine hairs on the antennal scapes that are diagnostic for the species. Provide a light source during the day to encourage activity. ^[1]

Frequently Asked Questions

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References