Polyrhachis trapezoidea

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Northern Australia, from Torres Strait to Gladstone, Queensland, and northern Northern Territory, in open eucalypt forests and savannah woodlands ^[1].
• Colony Type: Unconfirmed, no specific literature on queen number or social structure.
• Size & Growth:
  • Queen: 9.63-11.09 mm ^[1]
  • Worker: 7.61-9.42 mm ^[1]
  • Colony: Unknown, no context data on maximum colony size.
  • Growth: Moderate, inferred from related Polyrhachis species.
  • Development: Unknown, no context data on development time. (Development time is unclear, based on Formicinae patterns, it may vary with temperature.)
• Antkeeping:
  • Temperature: Keep warm, around 24-28°C, based on tropical distribution ^[1].
  • Humidity: Keep nest substrate consistently moist but not waterlogged, as pupal cocoons need humidity ^[2].
  • Diapause: No, inferred from tropical range ^[1].
  • Nesting: Ground-nesting species ^[1]. Use soil or Y-tong/plaster nests with moisture for cocoons ^[2].
• Behavior: Workers are generally calm but will defend the nest if threatened. They can spray formic acid as defense, typical for Formicinae. Escape risk is moderate for medium-sized ants, use standard barriers.
• Common Issues: cocoon desiccation, pupal cocoons need humidity to develop, dry conditions kill pupae., temperature drops below 22°C can slow brood development., colonies may struggle if kept too dry, monitor substrate moisture., escape prevention is needed for medium-sized ants, use standard barriers., slow founding, queens may take months to raise first workers.

Nest Preferences and Setup

Polyrhachis trapezoidea is a ground-nesting species that excavates chambers in soil ^[1]. In captivity, use naturalistic setups with soil or formicarium-style nests like Y-tong or plaster. Maintain moisture for pupal cocoons, keep substrate damp but not waterlogged ^[2]. Chambers should be scaled to medium-sized ants (7-9 mm workers). Avoid dry setups to prevent cocoon desiccation.

Feeding and Diet

Based on typical Polyrhachis patterns, this species is omnivorous. Offer protein sources like small insects and sugar sources like honey water. Feed protein 2-3 times per week and provide constant sugar water. Remove uneaten prey after 24-48 hours to prevent mold.

Temperature and Seasonal Care

Keep nest area warm, around 24-28°C, based on tropical distribution ^[1]. Use a heating cable for a temperature gradient. Avoid temperatures below 22°C, as they can slow brood development. No diapause needed, maintain stable warmth year-round.

Behavior and Colony Dynamics

Workers are calm but defensive, spraying formic acid when threatened. They are active foragers on the ground. Unlike arboreal relatives, they do not weave nests. Pupal cocoons require humidity for development ^[2]. Colony growth is moderate, founding queens may take months to raise first workers.

Escape Prevention

Workers are medium-sized (7-9 mm), with moderate escape risk. Use Fluon or similar barriers on test tubes and formicarium openings. Ensure all connections are secure to prevent escapes.

Frequently Asked Questions

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References