Ancyridris polyrhachioides

Ancyridris polyrhachioides

Ancyridris polyrhachioides are large, spiny black ants from the mountains of Papua New Guinea. Workers reach nearly 6 mm in length and carry distinctive hooked spines on their thorax and waist ^[1]. They live in montane forests above 1,500 meters elevation in the New Guinean cordillera ^[2]. Science has only ever documented workers, no queens or males have ever been found ^[1]. The first specimens were discovered in 1932 inside the stomach of a flycatcher bird collected on Mount Misim ^[1]. Additional workers have been found visiting honey baits and foraging on vegetation in forest habitats ^[1]. Their unusual body plan, including 12-segmented antennae and reduced frontal carinae, places them in a rare genus that forms a distinct evolutionary group with Lordomyrma and Propodilobus ^[3][2].

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Montane forests of Papua New Guinea, above 1,500m elevation ^[2]
• Colony Type: Unknown, only worker caste documented ^[1]
• Size & Growth:
  • Queen: Unknown, no queens documented
  • Worker: Nearly 6 mm ^[1]
  • Colony: Unknown
  • Growth: Unknown
  • Development: Unknown, founding behavior never observed (Development timeline cannot be estimated without knowledge of reproductive behavior or brood development.)
• Antkeeping:
  • Temperature: Cool montane conditions, approximately 18-22°C (inferred from elevation data ^[2])
  • Humidity: High humidity required, maintain damp substrate similar to cloud forest floor conditions
  • Diapause: Unknown
  • Nesting: Likely in rotting wood or soil in montane forests, use moist wood or plaster nests with good humidity retention
• Behavior: Unknown temperament, 6mm size requires standard escape prevention with sealed gaps and fine mesh
• Common Issues: only workers have ever been documented, making colony founding impossible with current knowledge, unknown temperature requirements risk colony failure if attempted, extreme rarity and limited distribution make obtaining specimens nearly impossible, lack of knowledge about diet and social structure prevents proper care

Natural History and Distribution

These ants come from the mountains of Papua New Guinea. Researchers have collected them at elevations above 1,500 meters in the New Guinean cordillera ^[2]. The type specimens came from Mount Misim in the Morobe District, where they were found inside a flycatcher's stomach in 1932 ^[1]. This suggests they forage where birds hunt, likely in the forest canopy or understory. Workers have also been observed at honey baits and foraging on vegetation in forest habitats ^[1]. The genus Ancyridris contains at least six undescribed species in addition to this one, often with up to four species living in the same area ^[2].

Housing and Environment

Since no queens have ever been found, standard colony founding is impossible. If you somehow obtained workers, house them in conditions matching their montane forest home. Keep temperatures cool, around 18-22°C, based on their collection elevation above 1,500 meters ^[2]. Maintain high humidity similar to cloud forest conditions. Use a nest with moist rotting wood or plaster that stays damp but not wet. Workers are nearly 6 mm long ^[1], so use standard fine mesh for ventilation and ensure all gaps are sealed.

Feeding

Workers have been observed visiting honey baits in the field ^[1], so they likely accept sugar water or diluted honey. They forage on vegetation, probably hunting small insects and other arthropods. Offer small live prey like fruit flies or tiny crickets. However, workers alone cannot start a colony, without a queen, they will eventually die off.

The Missing Reproductives

Science has never documented a queen or male of this species ^[1]. This could mean queens are extremely rare, live underground, or that the species reproduces in an unusual way not yet observed. Some related ants in the tribe Crematogastrini have wingless queens that look like workers, but this remains speculation for Ancyridris. Until someone discovers how these ants found colonies, keeping them is not feasible.

Frequently Asked Questions

References