Dolichoderus pilinomas

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Known only from Western Sarawak in northwestern Borneo (Gua Kapur/Fairy Cave area at 1°N latitude). They live in tropical rainforest conditions in a cave system. ^[1]
• Colony Type: Monogyne, single queen colonies. Queens are ergatoid (wingless) with fused mesonotum. ^[1]
• Size & Growth:
  • Queen: ~6.3 mm total length ^[1]
  • Worker: ~4.2-5.1 mm total length ^[1]
  • Colony: Very small, the only documented colony was small ^[1]
  • Growth: Unknown
  • Development: Unconfirmed, no development data exists for this species. (No specific development studies exist.)
• Antkeeping:
  • Temperature: Keep at 24-28°C, they are a tropical Bornean species from near the equator.
  • Humidity: High humidity required, think damp tropical cave environment. Keep nest substrate consistently moist but not waterlogged.
  • Diapause: No, being a tropical species from near the equator, they do not require hibernation or winter rest.
  • Nesting: Based on their natural history as cave-dwelling herdsmen ants, they likely prefer enclosed nests with narrow chambers. A Y-tong (AAC) nest or plaster formicarium with tight chambers would work well. They keep mealybugs in bivouac-like structures, so the nest should have space for this symbiosis.
• Behavior: These are docile, non-aggressive ants that focus on tending their mealybug partners rather than defending territory. Workers are small but active, carrying mealybugs between nest chambers. Their small size means they could slip through small gaps, so standard escape prevention is recommended.
• Common Issues: very limited availability, this species is rarely available in the antkeeping hobby due to its restricted range, specialized diet, they require mealybugs oraphid substitutes for their honeydew source, which complicates feeding, small colony size means they are fragile and slow to grow, tropical humidity requirements can be challenging to maintain consistently, no captive breeding data exists, wild-caught colonies may struggle in captivity, queen is ergatoid (wingless) which may affect how colonies establish

The Herdsmen Lifestyle

Dolichoderus pilinomas is one of the 'herdsmen ants', a fascinating group that has evolved a mutualistic relationship with mealybugs. Workers carry the mealybugs (Borneococcusbauensis) around in their nest and tend them like farmers tending livestock. The mealybugs feed on plant sap and produce honeydew, a sugary secretion that the ants consume. This partnership is so specialized that the ants and mealybugs have become dependent on each other. In captivity, you would need to maintain a colony of mealybugs oraphid substitutes to simulate this natural relationship. The mealybugs are kept within a bivouac-like nest structure, which is different from typical ant nests. ^[1]

Queen and Colony Structure

The queen of D. pilinomas is unusual, she is ergatoid, meaning she is wingless and worker-like in appearance. She has vestigial wing buds and a fused mesonotum (the middle section of her thorax is fused together). This is different from most ant queens that have full wings and distinct thoracic segments. The documented colony was monogyne, meaning it had a single queen. The colony was also very small, one of the smallest known in the cuspidatus group. This suggests that D. pilinomas may be a slow-growing species that maintains relatively small colonies even at maturity. ^[1]

Housing and Nest Setup

Because this is a rare species with no captive breeding history, housing recommendations are based on inference from their natural history. They are cave-dwelling ants from tropical Borneo, so they need high humidity and stable temperatures around 24-28°C. A Y-tong (AAC) nest or plaster formicarium with tight, appropriately-sized chambers would work well. The chambers should be scaled to their small worker size. Given their herdsmen lifestyle, the nest should have enough space to accommodate mealybug colonies. Test tubes can work for founding colonies, but you would need to eventually move them to a setup that allows for the mealybug symbiosis. Use standard escape prevention despite their small size.

Feeding and Diet

In the wild, D. pilinomas gets much of its nutrition from the honeydew produced by their mealybug partners. The workers also likely supplement with small insects and other protein sources. In captivity, you would need to provide: 1) A source of honeydew, either live mealybugs/aphids or sugar water/honey as a substitute, 2) Small protein sources like fruit flies, pinhead crickets, or other tiny insects. Sugar acceptance is likely given their honeydew-feeding habit, but the mealybug relationship is essential for long-term colony health. This makes them a challenging species to keep, you are essentially committing to maintaining two colonies (ants and mealybugs).

Temperature and Seasonal Care

As a tropical species from near the equator in Borneo, D. pilinomas does not experience cold winters or seasonal temperature drops. They require year-round warm conditions around 24-28°C. Unlike temperate species, they do not need diapause or hibernation periods. Temperature should be stable, avoid drafts or cooling. A heating cable on one side of the nest can create a gentle gradient, but ensure the heating element is placed on top of the nest rather than underneath to prevent excessive drying. Room temperature within this range is acceptable if your home stays consistently warm.

Frequently Asked Questions

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References