Polyrhachis scissa

Polyrhachis scissa

Polyrhachis scissa is a medium-sized arboreal ant native to southern India and Sri Lanka. Workers measure 6.4-7.2mm and are entirely black with a distinctive semiopaque appearance on the mesosoma and characteristic spines on the petiole. This species belongs to the subgenus Hemioptica, which is recognized by its unique thorax structure. Queens are larger at 8.4-8.7mm and closely resemble workers ^[1][2].

What makes P. scissa special is its silk-weaving behavior, these ants construct flexible carton nests using larval silk, building them on shrubs and branches about 2 meters above ground. This arboreal nesting habit combined with their silk-weaving ability makes them one of the most interesting Polyrhachis species for advanced antkeepers. They are found in both wet and dry zones of Sri Lanka, typically in monsoon forest habitats near forest edges ^[1][3].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Southern India (Karnataka, Kerala, Tamil Nadu, West Bengal) and Sri Lanka in the Indomalaya region. Found in monsoon forests and forest edges, typically nesting on shrubs and bamboo at jungle borders ^[1][4][3].
• Colony Type: Colony structure is not well-documented. Likely single-queen (monogyne) based on typical Polyrhachis patterns, but this is unconfirmed.
  • Founding: Claustral
• Size & Growth:
  • Queen: 8.4-8.7mm ^[1]
  • Worker: 6.4-7.2mm ^[1]
  • Colony: Unknown, likely moderate colonies based on related Polyrhachis species
  • Growth: Moderate, estimated based on typical Formicinae development
  • Development: Estimated 6-8 weeks at optimal temperature based on genus patterns (Development time is not directly studied for this species. Estimates based on typical Formicinae development at 24-27°C.)
• Antkeeping:
  • Temperature: Keep at 24-27°C. They come from a tropical climate and need warmth. A gentle heat gradient allows them to regulate their temperature ^[1].
  • Humidity: High humidity (70-80%) is essential. These are arboreal ants from humid monsoon forests, maintain moisture in the nest and provide a water source. Mist regularly but ensure ventilation to prevent mold.
  • Diapause: Unconfirmed, likely no true diapause given their tropical origin, but may show reduced activity during cooler periods. Monitor colony behavior.
  • Nesting: Arboreal specialists, they need vertical space with branches, twigs, or artificial structures to climb and nest on. A naturalistic setup with live plants or cork bark positioned vertically works well. They will construct silk nests, so providing suitable surfaces for weaving is beneficial. A Y-tong or acrylic nest can work if connected to a foraging area with climbing structures.
• Behavior: Polyrhachis scissa is generally calm and not particularly aggressive. When threatened, workers hide beneath leaves, typical defensive behavior for the genus. They are arboreal and spend most of their time climbing on vegetation. Escape risk is moderate due to their medium size, but standard barriers work well. They are active foragers and will readily explore their environment ^[1].
• Common Issues: high humidity requirements can lead to mold if ventilation is inadequate, arboreal nesting means they need vertical space, horizontal setups often result in stressed colonies, silk-weaving behavior may be disrupted in artificial nests without suitable surfaces, wild-caught colonies may have parasites or diseases that cause colony failure, slow founding means new colonies need patience, queens may take months to raise first workers

Nest Preferences and Housing

Polyrhachis scissa is an arboreal species that builds silk carton nests on shrubs and branches in the wild. In captivity, you need to replicate this vertical, silk-friendly environment. The best approach is a naturalistic setup with live plants, cork bark, or twigs positioned vertically. The ants will weave silk between surfaces to create their nest structure.

For a more controlled setup, you can use a Y-tong or acrylic formicarium connected to a spacious foraging area filled with branches, vines, or artificial plants for climbing. The key is providing vertical surfaces and edges where they can attach silk. Some keepers have success with cork bark leaned against the side of the enclosure, the ants will often build nests against these surfaces.

Avoid horizontal, ground-level-only setups. These ants are arboreal and become stressed without access to vertical space. The nest area should be humid while the foraging area can be slightly drier with good ventilation to prevent mold buildup. ^[2][1]

Feeding and Diet

Like most Polyrhachis species, P. scissa is omnivorous with a preference for sugary liquids and protein. Feed them sugar water, honey, or diluted maple syrup as a constant carbohydrate source. For protein, offer small insects like fruit flies, small crickets, mealworms, or other appropriately-sized prey.

In the wild, they forage for honeydew and small invertebrates in the canopy. In captivity, they typically accept most standard ant foods. Feed protein 2-3 times per week, and keep a sugar source available at all times. Remove uneaten prey after 24-48 hours to prevent mold.

Their arboreal lifestyle suggests they may also accept honeydew substitutes more readily than some ground-nesting species. Observe your colony's preferences and adjust feeding accordingly. ^[1]

Temperature and Seasonal Care

Being from tropical India and Sri Lanka, P. scissa requires warm conditions year-round. Maintain temperatures between 24-27°C in the nest area. You can create a gentle temperature gradient by placing a heating cable or mat on one side of the enclosure, this allows the ants to regulate their temperature by moving between warmer and cooler areas.

Avoid temperatures below 20°C for extended periods, as this can weaken the colony. Room temperature in most homes (22-25°C) is often suitable, but monitor your colony's activity. Active colonies indicate good conditions, if workers become sluggish and cluster together, they may need more warmth.

Unlike temperate species, they likely do not require a true hibernation period. However, slight seasonal variations in activity are normal. Reduce feeding slightly during cooler months when the colony is less active, but maintain basic warmth. ^[1]

Behavior and Colony Dynamics

Polyrhachis scissa workers exhibit typical Polyrhachis defensive behavior, when threatened, they retreat beneath leaves or other surfaces rather than attacking. This makes them a relatively calm species to handle, though they can bite if provoked.

The colony will grow gradually from the founding stage. A newly mated queen will seal herself in a chamber and raise the first brood alone. This founding period can take several months, so patience is essential. The first workers (nanitics) will be smaller than mature workers.

As the colony grows, they will establish foraging trails and explore their environment. They are good climbers and will readily ascend branches, plants, or other structures. A well-designed enclosure with vertical elements will see the most natural behavior. ^[1]

Frequently Asked Questions

References