Polyrhachis bicolor

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to Southeast Asia (including Thailand, Myanmar, Laos, Vietnam, Philippines, Indonesia), New Guinea, and northern Australia (Northern Territory). Inhabits monsoon rainforests and lowland forests, where it builds silk-and-debris nests in the canopy of trees and shrubs ^[1][4][5].
• Colony Type: Monogyne – single queen per colony. The colony is polydomous, meaning it maintains multiple nest sites connected by trails ^[3].
• Size & Growth:
  • Queen: 8.97 mm ^[1]
  • Worker: 6.00–7.06 mm ^[1]
  • Colony: Not documented in scientific literature, likely no more than a few hundred workers based on related Polyrhachis
  • Growth: Moderate
  • Development: Approximately 6–8 weeks at optimal temperatures (25–28°C), based on typical tropical Polyrhachis development (Development is highly temperature‑dependent. Exact timeline for this species has not been recorded.)
• Antkeeping:
  • Temperature: Tropical species that requires stable warmth. Keep at 24–28°C. A heating cable on one side of the nest helps create a gradient ^[1][4].
  • Humidity: Moderate to high humidity. Mist the enclosure occasionally but ensure good ventilation, as the ants nest in open foliage. Keep the nest substrate damp but not waterlogged ^[1][5].
  • Diapause: No – as a tropical species, Polyrhachis bicolor does not need hibernation. Can be kept at stable warm temperatures year‑round ^[4].
  • Nesting: Arboreal setup is essential. Provide branches, artificial leaves, or dried foliage for them to weave into nests. A Y‑tong or plaster nest with added vertical space works, but a canopy‑style enclosure with plenty of attachment points is best ^[1][3].
• Behavior: Active, diurnal, and moderately aggressive when defending the nest. Workers forage in groups, using short‑term trails and group recruitment ^[6]. They collect fruit, sap, small prey, and dead insects ^[6]. Their primary defense is a bite followed by a spray of formic acid (typical of Formicinae). They are medium‑sized (6–7 mm) and not skilled escape artists, so standard barriers are sufficient.
• Common Issues: arboreal setup is mandatory – ground‑only nests will not be accepted, polydomous colonies may look like they are splitting, but this is normal – avoid interfering, weaving requires healthy larvae, a colony without brood cannot build nests, tropical humidity must be balanced with ventilation to prevent mold, queens may be attracted to moving objects (e.g., a finger) and leave the nest – avoid unnecessary disturbance ^[9]

Housing and Nest Setup

Polyrhachis bicolor needs an arboreal setup that mimics its natural canopy life. Unlike soil‑dwelling ants, these weaver ants build nests among leaves. Provide branches, artificial leaves, or dried plant stems that workers can weave together. A naturalistic enclosure with vertical space (e.g., a large container with netting and attached foliage) works best. You can supplement with small pieces of paper, fabric, or dried leaves for weaving. A test tube is only suitable for a founding queen, once workers appear, transfer them to a proper arboreal nest. Y‑tong (AAC) or plaster nests can be used if they include tall chambers and mesh for attaching foliage ^[1][3].

Feeding and Diet

Polyrhachis bicolor is an omnivore. In the wild it collects fruit, tree sap, small prey, and dead insects ^[6]. Offer sugar sources (honey water, sugar water, ripe fruit) and protein (small crickets, fruit flies, mealworms). Fresh banana or mango is often accepted. Protein should be offered 2–3 times per week. Remove uneaten food after 24 hours to prevent mold. These ants use group recruitment, so place food where foragers can find it and recruit nestmates ^[6]. They are not picky eaters and will accept most standard ant foods.

Temperature and Humidity

As a tropical species, Polyrhachis bicolor needs warmth. Keep the nest at 24–28°C. Use a heating cable on one side to create a gradient. For humidity, aim for a moist substrate but ensure good airflow – this species nests in open foliage and does not tolerate stagnant air. Mist the enclosure every few days, but avoid waterlogging. A water tube provides drinking water ^[1][4].

Weaver Behavior and Colony Structure

One of the most interesting traits of Polyrhachis bicolor is its weaving behavior. Workers use silk from larvae to bind leaves and debris into nest chambers ^[2][8]. This requires a healthy colony with larvae present. The colony is polydomous, meaning it maintains several connected nests spread across the enclosure ^[3]. This is normal – do not mistake it for a split or decline. Workers will move brood and themselves between nests as needed.

Growth and Development

Colony growth is moderate. A newly mated queen probably relies on stored reserves, but observations suggest she may need occasional feeding ^[7]. After the first workers appear, the colony grows slowly. Development from egg to worker takes about 6–8 weeks at 25–28°C (an estimate based on related Polyrhachis). The queen can live for many years. Patience is needed – it may take several months to reach 20–30 workers.

Handling and Temperament

Polyrhachis bicolor workers are not especially aggressive toward keepers. They will flee if disturbed but defend the nest if provoked. Their defense is a bite plus a spray of formic acid, which can irritate skin. At 6–7 mm, they are easy to contain with standard barriers (fluon, vaseline). When foraging, they are active and use group recruitment – you will see trails form once food is found. Occasionally a queen can be lured away by a moving object (e.g., a finger), so avoid tapping the nest ^[9].

Frequently Asked Questions

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References