Polyrhachis mucronata

Polyrhachis mucronata

Polyrhachis mucronata is a medium-sized arboreal ant found across Southeast Asia and northern Australia. Workers measure 5.3-6.5mm and queens reach 6.9-7.8mm, with a distinctive polished black body and reddish-brown legs ^[1]. Their most remarkable feature is their nest-building behavior, they weave silk produced by their larvae together with leaf fragments to create protective shelters on the undersides of rainforest leaves ^[1]. This species belongs to the Myrmhopla subgenus and is distinct from similar-looking ants due to its columnar petiole with two horizontal spines that wrap around the gaster ^[1]. The species ranges from eastern Indonesia and New Guinea south to northern Queensland, where it inhabits monsoon and lowland rainforests ^[1].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to Southeast Asia and northern Australia, ranging from eastern Indonesia and New Guinea to northern Queensland. Found in monsoon rainforests of Cape York Peninsula and lowland rainforests of the Wet Tropics ^[1].
• Colony Type: Monogyne, colonies have a single queen and do not have multiple nests per colony ^[2]. Queens are not parasitic and colonies are founded by single queens.
  • Colony: Monogyne
• Size & Growth:
  • Queen: 6.95-7.81mm ^[1]
  • Worker: 5.34-6.50mm ^[1]
  • Colony: Unknown for this species, likely moderate based on typical Polyrhachis patterns
  • Growth: Moderate, estimated based on related species
  • Development: Estimated 6-10 weeks at optimal temperature based on genus patterns (Direct development data unavailable, inferred from related Polyrhachis species. Cocoons are present, pupae are enclosed in silk cocoons ^[2].)
• Antkeeping:
  • Temperature: Keep at 24-28°C. These are tropical rainforest ants requiring warm, stable temperatures ^[1]. A heating cable on one side of the nest creates a gentle gradient.
  • Humidity: High humidity required, aim for 70-85%. They naturally live in rainforest understory where humidity stays consistently high. Keep nest substrate moist but not waterlogged, with good ventilation to prevent mold.
  • Diapause: No, these are tropical ants that do not require hibernation. Maintain warm conditions year-round ^[1].
  • Nesting: Arboreal specialists, they build silk-woven nests on leaves in the wild. In captivity, provide a vertical or naturalistic setup that allows for climbing and silk attachment. Y-tong nests or acrylic nests with rough surfaces for grip work well. Include small plant material or artificial leaves for them to weave onto.
• Behavior: Generally calm and non-aggressive compared to many Formicinae. Workers are active foragers that search for honeydew and small prey on vegetation. They are arboreal by nature, spending most of their time climbing rather than walking on flat surfaces. Escape risk is moderate, their medium size means standard barriers work well, but they are agile climbers. They may be more active at night in captivity.
• Common Issues: high humidity requirements can lead to mold if ventilation is poor, balance humidity with airflow, arboreal nature means they may not use horizontal test tube setups, provide climbing structures, tropical species will decline if temperatures drop below 22°C for extended periods, silk-weaving behavior requires rough surfaces or plant material to attach nests, smooth acrylic alone may not be ideal, wild-caught colonies may be stressed from arboreal collection and require careful acclimation

Nest Preferences and Housing

Polyrhachis mucronata is an arboreal species that naturally builds silk-woven nests on the undersides of rainforest leaves, primarily in the lower canopy zone ^[1]. In captivity, you should replicate this by providing vertical space and surfaces they can attach silk to. Y-tong (AAC) nests work well because the rough surfaces give workers something to grip and anchor their silk structures. Acrylic nests can also work if you add small pieces of plant material, artificial leaves, or rough-textured inserts for them to build on. Avoid completely smooth horizontal test tubes, these ants prefer to climb and may not settle well in flat setups. A naturalistic setup with live or artificial plants allows them to display their natural silk-weaving behavior, which is fascinating to watch.

Feeding and Diet

Like most Polyrhachis species, these ants are omnivorous with a preference for sweet liquids and protein. Feed them sugar water or honey regularly, and offer protein sources such as small insects (fruit flies, small crickets, mealworms) every few days. They are arboreal foragers in the wild, often tending aphids or collecting honeydew from tropical vegetation. In captivity, they typically accept a wide range of foods. Offer fresh food every 2-3 days and remove uneaten prey within 24 hours to prevent mold. A constant sugar water supply is recommended, you can use a cotton ball in a small container or specialized ant feeder.

Temperature and Humidity Requirements

These are tropical rainforest ants requiring warm and humid conditions. Maintain temperatures between 24-28°C year-round, they do not tolerate cool conditions and may become sluggish below 22°C. A heating cable placed on part of the nest can help maintain warmth, but always provide an unheated area so workers can regulate their own temperature. Humidity should stay high at 70-85%, mist the outworld occasionally and keep nest substrate moist but never waterlogged. Good ventilation is essential to prevent mold while maintaining humidity. Because they nest in leaves in the wild, they are accustomed to high ambient moisture but also some air movement. ^[1]

Colony Structure and Development

P. mucronata colonies are monogyne, meaning they have a single queen who is the sole egg-layer ^[2]. Unlike some Polyrhachis species that have multiple nests per colony, this species maintains a single nest ^[2]. Queens are relatively large at 6.95-7.81mm and workers range from 5.3-6.5mm ^[1]. Their pupae are enclosed in cocoons, which is a distinguishing feature of the Myrmhopla subgenus ^[1]. Colony growth is moderate, expect several months before seeing the first workers (nanitics) emerge, and several years to reach moderate colony sizes. The silk-weaving behavior begins once workers are established, as they use larval silk to construct their nest structures.

Behavior and Temperament

These ants are generally calm and less aggressive than many Formicinae species. Workers are active climbers rather than ground-dwellers, and they spend considerable time on vegetation in the wild. Their silk-weaving behavior is a fascinating defensive adaptation, by attaching leaves together with larval silk, they create sheltered chambers that protect the colony from predators and weather. In captivity, you may observe workers pulling at fabric or plant material with their mandibles, attempting to weave it into structures. They are not known to sting and pose no danger to keepers. Their moderate size and calm temperament make them an interesting species for antkeepers who can provide the arboreal setup they need. ^[1]

Frequently Asked Questions

References