Myrmica rugiventris

Myrmica rugiventris

Myrmica rugiventris is a small red ant species native to the southwestern United States, found primarily in Arizona, Colorado, and California. Workers are typical Myrmica-sized at 4-6mm with the characteristic reddish-brown coloration and a functional stinger. This species belongs to the punctiventris group and is considered rare in the wild, inhabiting chaparral, oak woodland, and coastal scrub habitats. As a generalist predator and scavenger in the Myrmicini tribe, they hunt small invertebrates and scavenge for protein sources. What makes M. rugiventris notable is its limited distribution and the mystery surrounding its introduction history, early records suggest it may have arrived in Arizona via camel supplies, though this remains unconfirmed.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to the Nearctic region, specifically the southwestern United States (Arizona, Colorado, California). Found in chaparral, oak woodland, and coastal scrub habitats ^[1][2]. This is a rare species with limited distribution.
• Colony Type: Monogyne (single-queen) colonies based on typical Myrmica patterns. Queens are known to have reproductive potential ^[3].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Estimated 6-8mm based on genus typical size range
  • Worker: Estimated 4-6mm based on genus typical size range
  • Colony: Unknown for this specific species, likely moderate colony size under 500 workers based on related Myrmica species patterns
  • Growth: Moderate, typical Myrmica development rates
  • Development: Estimated 6-10 weeks at optimal temperature based on genus-level data for related species (Development time inferred from typical Myrmica patterns, specific data for this species is unavailable)
• Antkeeping:
  • Temperature: Keep around 20-24°C with a gentle gradient. Room temperature within this range works well. Related Myrmica species tolerate 18-25°C ^[4].
  • Humidity: Moderate humidity around 50-70%. Keep nest substrate slightly moist but not waterlogged. Provide a water tube for drinking access.
  • Diapause: Yes, Myrmica species require winter diapause. Keep at 5-10°C for 3-4 months (October-March in Northern Hemisphere) ^[4].
  • Nesting: Y-tong (AAC) nests or test tube setups work well. This species likely prefers soil-based nests similar to other Myrmica. Provide a shallow water reservoir.
• Behavior: Workers are moderately aggressive and will sting if threatened. They are active foragers, hunting small prey and scavenging. Escape risk is moderate, standard test tube barriers and fluon on edges work well. Workers are smaller (4-6mm) so ensure lid seals are tight. They show typical Myrmica behavior: active, persistent, and defensive of their nest.
• Common Issues: colonies may fail to establish if founding queen is disturbed, minimize vibrations during claustral founding, winter diapause is essential, skipping hibernation will weaken and eventually kill the colony, small colony size means they are vulnerable to stress, avoid frequent moves or disturbances, escape prevention is important, workers can squeeze through small gaps despite their size, wild-caught colonies may carry parasites that can devastate captive colonies

Housing and Nest Setup

Myrmica rugiventris does well in standard antkeeping setups. Test tube setups work perfectly for founding colonies, use a test tube with a water reservoir separated by a cotton plug, giving the queen a dark chamber to seal herself in. For established colonies, Y-tong (AAC) nests with plaster or soil substrate work well. The species naturally nests in soil in chaparral and woodland habitats, so a naturalistic setup with damp soil can mimic their preferred conditions. Ensure the nest has chambers scaled to their worker size (4-6mm workers need appropriately sized passages). A shallow water tube should always be available for drinking access. ^[1][4]

Feeding and Diet

As generalist predators and scavengers, Myrmica rugiventris accepts a wide variety of foods. Protein sources should form the bulk of their diet: small insects like fruit flies, pinhead crickets, mealworms, and waxworms are readily accepted. They also scavenge and will take protein-based commercial ant foods. Sugar sources are important for energy, offer sugar water, honey, or diluted maple syrup regularly. A constant sugar water supply via a cotton ball or test tube works well. Feed protein prey 2-3 times per week, removing any uneaten prey after 24 hours to prevent mold. Fresh killed insects are more readily accepted than live ones initially. ^[3]

Temperature and Seasonal Care

Keep your colony at room temperature (20-24°C) with a slight thermal gradient if possible. A heating cable on one side of the nest can create this gradient, place it on top of the nest, not underneath, to avoid excessive drying. Myrmica species are cold-tolerant and benefit from seasonal temperature changes. During winter (October-March), move the colony to a cool location (5-10°C) for diapause. This winter rest period is essential for colony health, skipping hibernation leads to weakened colonies and reduced lifespan. Do not freeze the colony, a cold basement, garage, or refrigerator (not freezer) section works well. Resume normal temperatures gradually in spring. ^[4]

Behavior and Defense

Workers are active foragers that search for food both individually and through recruitment. Like other Myrmica species, they possess a functional stinger and will use it defensively when threatened. The sting is noticeable but not dangerous to healthy humans, it causes localized pain similar to a bee sting. Workers are moderately aggressive toward disturbances and will vigorously defend their nest. They are not escape artists in the same league as tiny species like Pheidole, but standard escape prevention (fluon on rim edges, tight-fitting lids) is still recommended. Colonies are typically calm when not disturbed but become alert and active when vibrations or light changes occur. ^[3][4]

Colony Establishment

When your queen arrives, prepare a clean test tube with a water reservoir. Place the queen gently in the tube and keep it dark and undisturbed for 2-4 weeks. The claustral queen will seal herself into the chamber and begin laying eggs. Do not feed during this founding phase, she survives entirely on her stored fat reserves. Once the first workers (nanitics) emerge, you can begin offering tiny amounts of food: a drop of sugar water and one or two small insect pieces. Wait another week before checking more closely. Growth is slow initially, be patient. Do not expose the founding chamber to direct light or vibrations during this critical period. ^[4]

Frequently Asked Questions

References