Polyrhachis lamellidens

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Native to East Asia: Japan, Korea, Taiwan, and China. Found in rotten logs, tree stumps, and occasionally underground in woodland habitats ^[1][2].
• Colony Type: Unconfirmed, based on subgenus patterns, likely both single-queen and multi-queen colonies exist, but not specifically confirmed for P. lamellidens ^[5].
• Size & Growth:
  • Queen: ~10-11 mm ^[1]
  • Worker: ~7-9 mm ^[1]
  • Colony: Up to 10,000 workers ^[3]
  • Growth: Moderate
  • Development: Unknown, no specific data available (Based on related Formicine ants, expect 6-10 weeks at optimal temperature.)
• Antkeeping:
  • Temperature: Keep at room temperature, roughly 20-25°C. This temperate species likely tolerates cooler conditions.
  • Humidity: Keep nest substrate consistently moist but not waterlogged, as they nest in rotting wood ^[1].
  • Diapause: Yes, based on temperate range, likely requires winter diapause. Nuptial flights in October-November indicate seasonal patterns ^[3].
  • Nesting: Prefer wood-based or plaster nests that hold moisture. Mimic rotting wood conditions ^[1][2].
• Behavior: Workers are defensive due to spines, making them unpalatable to predators like tree frogs ^[3]. They are omnivorous, feeding on honeydew, sap, and dead insects. Not aggressive but may bite. Escape risk is moderate due to size.
• Common Issues: temporary social parasitism makes founding difficult, queens need a host Camponotus colony ^[3][4]., vulnerable status in Japan may restrict wild collection ^[7]., slow colony growth during transition period ^[4]., mites can attach to petiole, check during maintenance ^[6]., fungal infection by Ophiocordyceps species is possible ^[7][8].

Colony Founding and Social Parasitism

This is the most challenging aspect of keeping P. lamellidens. In the wild, a newly mated queen must locate a nest of Camponotus japonicus or C. obscuripes. She captures a host worker, transfers scent from the worker to her body using her fore legs, then enters the host nest. The queen attaches herself to the host queen's neck and they stay in close contact for up to 2 weeks, transferring scent. Host workers cannot distinguish between the two queens and feed both. Eventually the P. lamellidens queen kills the host queen. Host workers then feed the parasite queen through winter while her ovaries develop. In spring, egg-laying begins with host workers tending the brood. Over time, host workers die and are replaced with P. lamellidens workers until the colony becomes pure lamellidens ^[4].

For antkeepers, this means you cannot establish a colony the normal way. You need an established Camponotus colony (preferably C. japonicus or C. obscuripes) to introduce the P. lamellidens queen to. Even then, success is not guaranteed, in laboratory trials, only 5 of 8 queens survived initial contact with host workers ^[4]. This is not a species for beginners.

Housing and Nest Preferences

In the wild, P. lamellidens nests in rotten logs, tree stumps, and sometimes underground ^[1]. They prefer damp, decaying wood in woodland areas. Nests are typically in large hollow sections of standing trees ^[3].

For captive housing, provide a setup that mimics rotting wood conditions. Wood-based formicaria or plaster nests that can hold moisture work well. You can also use test tubes with a water reservoir, but add some damp substrate like peat or wood chips to maintain humidity. They do not need arboreal setups, terrestrial or subterranean arrangements suit them fine. Ensure the nest material can absorb and hold moisture without becoming waterlogged.

Feeding and Diet

P. lamellidens are omnivorous and will accept a wide variety of foods. In nature, they feed on plant sap, aphid honeydew, and dead insects and other arthropods ^[6]. They are attracted to protein baits, and when food is placed near the nest entrance, large numbers of workers will recruit to the source.

In captivity, offer sugar water or honey as a constant energy source. For protein, provide dead insects (fruit flies, small crickets, mealworms) and other small arthropods. They are not strong hunters, they lack a sting and are more likely to scavenge than actively hunt live prey ^[6]. Feed protein 2-3 times per week and keep sugar sources available constantly. Remove uneaten prey after 24-48 hours to prevent mold.

Defense and Unique Adaptations

One of the key aspects of P. lamellidens is their defensive spines. Workers have large hook-like spines on their petiole that serve as effective defense against predators. Research using Japanese tree frogs (Hyla japonica) showed that intact workers are unpalatable, 27 out of 30 frogs that put an intact worker in their mouth spat it out. Workers without spines, however, were readily eaten (13 out of 14 frogs fed on them). The spines physically stick into the frog's mouth, making the ants difficult to swallow ^[3].

Queen spines are much smaller and less effective. Intact queens were palatable to frogs, all 8 frogs that took an intact queen in their mouth ate it without vomiting. This difference makes sense evolutionarily: workers need defense while the queen is protected inside the nest and later within the host colony ^[3].

Seasonal Care and Overwintering

As a species native to temperate regions (Japan, Korea), P. lamellidens experiences cold winters and requires a diapause period. Nuptial flights occur in October to November ^[3], after which mated queens either enter host ant nests or hibernate in dead wood before entering a host nest the following spring.

In captivity, reduce temperatures in winter to simulate natural conditions. A cool basement or unheated room around 10-15°C works well for 2-3 months. Reduce feeding during this period and minimize disturbance. Do not feed heavily during diapause. Resume normal temperatures and feeding in spring when the colony becomes active again.

Conservation and Ethical Considerations

P. lamellidens is designated as Vulnerable (VU) in Japan and Endangered Category II in the Japanese Ministry of Environment Red List ^[7][3]. Their habitat is decreasing due to residential and industrial development ^[8].

Before acquiring this species, consider whether the colony was ethically sourced. Wild collection may be restricted in Japan. Captive-bred colonies are preferable. If you do keep this species, avoid releasing any ants outside their native range (Japan, Korea, Taiwan, China). They could become invasive or disrupt local ecosystems.

Frequently Asked Questions

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References