Polyrhachis ulysses

Polyrhachis ulysses

Polyrhachis ulysses is a striking arboreal ant species native to the Solomon Islands, specifically recorded from Makira and Guadalcanal islands ^[1]. Workers are medium-sized ants with the characteristic spiny morphology of the Polyrhachis genus, featuring well-developed spines on the mesosoma. The species was first described by Forel in 1910 from the Solomon Islands ^[2]. As a member of the subgenus Myrmatopa, these ants are arboreal nesters that use larval silk to construct their nests among vegetation rather than nesting in soil ^[3]. Unlike many ants, they do not produce cocoons during pupation, the pupae are naked ^[4]. This is a tropical species from a warm, humid island environment, which shapes its care requirements in captivity.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Solomon Islands (Makira, Guadalcanal) in the tropical Pacific region ^[1]. This species lives entirely in arboreal habitats, weaving nests among vegetation using silk ^[3].
• Colony Type: Single-queen (monogyne) colonies based on typical Polyrhachis colony structure. Colonies are relatively small to moderate in size.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Estimated 10-12mm based on genus patterns for Polyrhachis species
  • Worker: Estimated 6-9mm based on typical Polyrhachis worker size range
  • Colony: Estimated several hundred workers based on related arboreal Polyrhachis species
  • Growth: Moderate, typical for tropical arboreal ants
  • Development: Estimated 6-8 weeks at tropical temperatures (25-28°C) (Development timeline is estimated based on related Polyrhachis species, direct observations for P. ulysses are not available)
• Antkeeping:
  • Temperature: Keep at 24-28°C (warm tropical conditions). Room temperature may suffice if your home is naturally warm, otherwise use a heating cable on one side of the nest to create a gentle gradient ^[3].
  • Humidity: High humidity is essential, aim for 70-80% relative humidity. These arboreal ants come from the humid Solomon Islands, so keep the nest substrate moderately moist but allow some drying areas. Regular misting or a water reservoir in the outworld helps maintain humidity ^[1].
  • Diapause: No, this is a tropical species that does not require hibernation. Maintain warm temperatures year-round ^[3].
  • Nesting: Arboreal setup is ideal. These ants naturally weave silk nests among vegetation, so provide climbing structures like branches, cork bark, or live plants. A naturalistic setup with vertical surfaces for webbing works well. Acrylic nests with chambers can work if paired with ample climbing space in the outworld ^[4][3].
• Behavior: Generally peaceful and not aggressive toward keepers. Workers are active foragers that will search for honeydew and small prey. They are escape artists due to their arboreal nature, ensure excellent barrier prevention (Fluon on rim edges). They are most active in warm, humid conditions and will readily explore climbing structures. Unlike many ants, they use silk to create webbed nests, so providing suitable materials for this behavior encourages natural colony maintenance ^[3].
• Common Issues: tropical humidity needs mean dry housing causes stress and colony decline, escape prevention is critical, they are agile climbers that will find any gap, lack of cocoons means pupae are vulnerable to disturbance, minimize nest inspections during pupation, cold temperatures below 22°C slow activity and can stress colonies, without climbing structures in the outworld, workers become stressed and may not forage properly

Housing and Nest Setup

Polyrhachis ulysses requires an arboreal-focused setup that mimics their natural tree-dwelling lifestyle. Unlike soil-nesting ants, these ants need vertical space and climbing structures to thrive. Provide branches, cork bark rounds, or artificial plants in the outworld for workers to traverse. The nest itself can be an acrylic formicarium with horizontal chambers, but the critical factor is giving them plenty of above-ground territory in the outworld for foraging and web-building ^[4]. A hybrid setup works well: a compact nest area connected to a spacious outworld with multiple climbing surfaces. Ensure the connection tubes are wide enough for easy traffic but consider escape prevention at all access points.

Feeding and Diet

As omnivorous arboreal ants, Polyrhachis ulysses accepts a varied diet. Offer sugar sources regularly, honey water, sugar water, or commercial ant nectar are all readily accepted. Protein is essential for colony growth: small insects like fruit flies, pinhead crickets, and mealworms work well. In their natural habitat, they forage for honeydew from aphids and scale insects, plus small arthropods. Feed protein prey 2-3 times per week depending on colony size, and keep sugar water available at all times. Remove uneaten prey after 24-48 hours to prevent mold. Young colonies may be shy about taking large prey, offer appropriately sized portions.

Temperature and Humidity Management

This tropical species demands warm, humid conditions year-round. Maintain temperatures between 24-28°C, this range supports normal activity and brood development. Temperatures below 22°C cause reduced activity and can stress colonies over time. Use a low-wattage heating cable if your room temperature runs cool, placing it on one side of the nest to create a gentle thermal gradient. Humidity should stay around 70-80%. In naturalistic setups, misting regularly maintains moisture. For acrylic nests, a water tube or cotton reservoir provides humidity. Avoid both excessive dryness (causes desiccation) and stagnant dampness (causes mold). Good ventilation helps balance these needs. ^[1][3]

Silk Weaving Behavior

One of the most fascinating aspects of keeping Polyrhachis ulysses is observing their silk-weaving behavior. Members of the subgenus Myrmatopa use larval silk to construct protective nest structures among vegetation ^[3]. Workers manipulate larvae during nest construction, using them as 'silk spools' to create webbed chambers. In captivity, provide materials like cotton wool, small fabric pieces, or live plant leaves for them to weave into. This behavior is most active when colonies are established and comfortable. Watching workers coordinate to create silk bridges and chambers is one of the joys of keeping this species. Do not disturb active weaving, let the colony complete their structures naturally.

Colony Founding and Growth

New colonies start with a claustral queen sealing herself in a small chamber. As a Formicinae species, the queen has fat reserves to survive until her first workers emerge without foraging ^[4]. The founding chamber should be humid and warm. First workers (nanitics) are typically smaller than mature workers. Growth is moderate, expect 6-10 workers by month 2-3,with growth accelerating as the colony reaches 20-30 workers. Unlike cocoon-making species, P. ulysses produces naked pupae that may appear white and vulnerable. Avoid disturbing the nest during pupation. A healthy mature colony may reach several hundred workers over 2-3 years under optimal conditions.

Handling and Temperament

Polyrhachis ulysses is generally calm and not prone to biting or stinging. Workers are curious foragers that will investigate disturbances but rarely show aggression toward keepers. They are excellent escape artists due to their arboreal nature and agile movements, always use Fluon or other barriers on enclosure rims. When threatened, they may retreat into their silk nests rather than engage. They do not have a functional stinger (Formicinae spray formic acid instead), making them safe for handling. However, always wash hands before working near the colony as residues can stress ants. Their peaceful temperament makes them an interesting display species, especially when observing their weaving behavior.

Frequently Asked Questions

References