Polyrhachis caeciliae

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Tropical rainforests in Borneo, Sumatra, Java, and Malaysia. Recorded in the Maliau Basin Conservation Area in Sabah at locations like Ginseng Camp and Agathis Camp ^[2][3].
• Colony Type: Single-queen (monogyne) colonies are likely, based on typical Polyrhachis patterns. Monogyne means a colony has only one reproductive queen.
• Size & Growth:
  • Queen: size unknown, inferred from Polyrhachis genus (~8-12mm)
  • Worker: size unknown, inferred from Polyrhachis genus (~5-8mm)
  • Colony: Unknown for this species. Related Polyrhachis species may reach several hundred workers.
  • Growth: Moderate
  • Development: Estimated 6-10 weeks at warm tropical temperatures, based on typical Formicinae development patterns. (Development speed depends on consistent warmth and humidity.)
• Antkeeping:
  • Temperature: Keep warm and stable, roughly low-to-mid 20s°C. A slight gradient helps workers regulate.
  • Humidity: Keep the nest substrate consistently moist but not waterlogged. Provide a water source for drinking.
  • Diapause: No, this is a tropical species that stays active year-round.
  • Nesting: Likely nests in decaying wood or soil. In captivity, a plaster nest, soil nest, or 3D-printed nest with tight chambers works best. They prefer dark, secure spaces.
• Behavior: Generally calm and not highly aggressive. Workers forage for small insects and likely collect honeydew. They lack a functional sting and defend themselves by biting and spraying formic acid. Escape risk is moderate due to their size, so use standard barrier precautions like fluon on nest rims.
• Common Issues: temperatures dropping below 20°C can slow development or kill brood, substrate drying out causes colony stress and brood loss, limited research means you must observe your colony closely and adjust care, wild-caught queens may carry parasites or mites, founding phase takes time, do not disturb the queen during this period

Natural History and Distribution

Polyrhachis caeciliae lives in the Indomalaya region. You can find them in Borneo, Sumatra, Java, and Malaysia. The species was first described by Forel in 1912 from Sumatra. A later name given to a specimen from Java, Polyrhachis caeciliae, was recognized as the same species by Kohout in 1998 ^[1]. In Borneo, researchers recorded them in the Maliau Basin Conservation Area in Sabah. They appear at specific sites like Ginseng Camp and Agathis Camp ^[2][3]. This is a lowland tropical forest species that thrives in warm, humid conditions. The subgenus Myrmhopla contains several similar species, all distributed across this region.

Housing and Nest Preferences

In captivity, Polyrhachis caeciliae does well in setups that mimic their natural tropical forest habitat. A naturalistic terrarium-style setup with moist soil substrate works well. Use a mix of soil and peat that holds moisture without becoming waterlogged. Alternatively, a Y-tong (AAC) nest, plaster nest, or 3D-printed nest with narrow chambers maintains the humidity they need. They prefer dark, tight spaces for their nest chambers. Since this species may be semi-arboreal, adding some vertical elements like twigs or fake plants gives them options. Keep the outworld at room temperature while ensuring the nest stays warm. Always provide a shallow water dish. These ants need access to drinking water.

Temperature and Humidity Requirements

As a tropical species from Borneo, Polyrhachis caeciliae requires warm conditions. Keep the nest area in the low-to-mid 20s°C. This range supports brood development. A heating cable or mat on one side of the nest creates a gentle gradient. Room temperature within this range works well. Humidity should stay high. The substrate should feel consistently moist but never soggy. Mist occasionally and use a water reservoir in the nest to maintain humidity. Avoid placing the nest near air conditioning or drafts that could cause temperature swings. These ants are not tolerant of cool conditions. Temperatures below 20°C for extended periods can stress the colony.

Feeding and Diet

Like other Polyrhachis species, these ants are omnivorous. Offer protein sources like small insects (fruit flies, small crickets, mealworms) and sugar sources (honey water, sugar water). In nature, they likely forage for small invertebrates and collect honeydew from aphids or scale insects. Feed protein two to three times per week. Keep a constant sugar source available. Remove uneaten prey after 24 to 48 hours to prevent mold. A varied diet helps. Try different small prey items to see what they prefer. Fresh killed insects work better than dried ones. They may accept specialized ant foods as supplements.

Colony Development and Growth

The founding phase for Polyrhachis caeciliae follows typical Formicinae patterns. The queen seals herself in a chamber and raises the first workers alone using stored fat reserves. First workers are typically smaller than mature workers. Development from egg to worker likely takes six to ten weeks at optimal tropical temperatures. Growth rate is moderate. Do not expect rapid expansion. A healthy colony may reach several hundred workers over several years. Be patient during the founding phase. Disturbing the queen or nest during this critical period often leads to failure. Once established, colonies grow steadily but not explosively.

Behavior and Temperament

Polyrhachis ants are generally calm and less aggressive than some genera. Workers are moderately active and will forage in the outworld for food. When food is found, they may recruit nestmates through simple chemical signaling rather than the elaborate tandem running seen in some ants. The spines on their thorax serve as a defense mechanism. They are harder for predators to handle. They are not particularly aggressive toward keepers and rarely bite. Standard escape prevention (fluon on rim, tight-fitting lids) is sufficient. They are not known as escape artists. Observe your colony's activity patterns and adjust feeding and care accordingly.

Frequently Asked Questions

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References