Myrmica arisana

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Mountainous central Taiwan (Nantou, Chiayi provinces) at elevations of 1700-2500m. Found under stones on south-facing banks by roadsides and in tree stumps at forest edges and glades ^[3].
• Colony Type: Likely monogyne (single queen) with possible oligogyne (few queens). Forms large polycalic populations spanning multiple connected nests under stones. No mature queens were caught in extensive field surveys, suggesting the species is probably not especially polygynous ^[3].
• Size & Growth:
  • Queen: ~5-7mm, inferred from genus typical size and close relation to M. rubra.
  • Worker: ~4-6mm, inferred from genus patterns.
  • Colony: Large polycalic colonies with hundreds of workers across multiple connected nests in the wild ^[3].
  • Growth: Moderate, typical Myrmica development timeline at optimal temperature.
  • Development: 6-10 weeks at optimal temperature (around 20-22°C). This is estimated based on typical Myrmica genus development. (Development time is inferred from related Myrmica species, direct observations for M. arisana are not available.)
• Antkeeping:
  • Temperature: Keep nest area at 20-24°C. These are mountain ants from cool high-elevation habitats, so avoid overheating. Room temperature is often suitable. A gentle gradient allowing cooler areas (18-20°C) is beneficial.
  • Humidity: Moderate to high humidity. Keep nest substrate consistently moist but not waterlogged. These ants naturally inhabit damp mountain banks under stones, the substrate should feel damp to the touch with some drier areas available.
  • Diapause: Yes, Myrmica ants require a winter dormancy period. Provide 2-3 months at 5-10°C during winter months (roughly November-February in temperate regions). This mimics their natural high-elevation seasonal cycle.
  • Nesting: Y-tong (AAC) nests or plaster nests work well. Provide narrow chambers scaled to their medium size. Naturalistic setups with flat stones over moist substrate also replicate their natural under-stone nesting. Keep nest dark as they prefer concealed chambers.
• Behavior: Workers are very aggressive and will sting freely when threatened, more defensive than many Myrmica species. They are active foragers that readily hunt small invertebrates and collect honeydew. They have good escape prevention needs due to their medium size and active nature. Colonies are polydomous (multi-nest) in nature, so they may benefit from connected outworlds as they grow. Males were observed leaving nests on August 11th, suggesting nuptial flights occur in mid-August ^[3].
• Common Issues: aggressive sting, handle with care and use gloves when servicing the colony, high-elevation origin means they are sensitive to overheating, keep away from direct heat sources, polycalic colony structure may require more space or connected nests as the colony grows, winter dormancy is essential, skipping diapause can weaken or kill the colony, wild-caught colonies may carry parasites that can devastate captive colonies, this species serves as a host for Phengaris atroguttata butterfly larvae, ensure food sources are properly cleaned

Housing and Nest Setup

Myrmica arisana does well in Y-tong (AAC) nests or plaster nests with narrow chambers scaled to their medium size. They naturally nest under stones in the wild, so a naturalistic setup with flat stones placed over moist soil or plaster also works well. The key is providing dark, concealed chambers that stay consistently moist. Because they form polycalic (multi-nest) colonies in nature, you might eventually connect multiple formicaria with tubing to give them more space. Test tube setups work for founding colonies, use a water reservoir tube for humidity and keep it in darkness. Avoid overheating by placing the nest in a cool area of your room, away from direct sunlight or heating elements. ^[3]

Feeding and Diet

Myrmica arisana is a generalist omnivore like other Myrmica species. Offer protein sources such as small insects (fruit flies, small crickets, mealworms), and provide sugar water, honey, or diluted sugar syrup as an energy source. They will also collect honeydew from aphids if available. Feed protein 2-3 times per week and keep sugar water constantly available. Remove uneaten prey after 24-48 hours to prevent mold. These are active foragers, so they will readily search out and consume prey items.

Temperature and Seasonal Care

These are high-elevation mountain ants from Taiwan, so they prefer cooler temperatures than many tropical species. Keep the nest area at 20-24°C, with cooler areas around 18°C available. Avoid temperatures above 28°C as this can stress or kill them. During winter (roughly November-February), provide a diapause period at 5-10°C, this is essential for colony health and mimics their natural seasonal cycle in the mountains. Place the colony in an unheated garage or refrigerator during winter dormancy. Do not feed during diapause but keep the substrate slightly moist. ^[3]

Behavior and Handling

Myrmica arisana workers are notably more aggressive than many Myrmica species, they sting freely when disturbed and will aggressively defend their nest. When servicing the colony, work slowly and carefully, and consider wearing gloves. They are active foragers and will readily explore their outworld during daytime. Their medium size and active nature mean escape prevention should be good, use fluon barriers and secure lids. Colonies can be polydomous, so they may benefit from having multiple connected foraging areas as they grow. ^[3]

Colony Development

A claustral queen will seal herself in a chamber and raise the first brood alone using stored fat reserves. The first workers (nanitics) will be smaller than normal workers. After the nanitics emerge, the colony enters a growth phase. Myrmica colonies typically grow moderately, expect 6-10 weeks from egg to first worker at optimal temperature. Growth rate is moderate, not as fast as some tropical species. Colonies can live for many years with a healthy queen producing workers seasonally.

Frequently Asked Questions

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References