Mycetomoellerius ruthae

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Neotropical region, Ecuador and Trinidad and Tobago. Found in semideciduous forest (Maracá), Campo Cerrado, and Cerrado sensu stricto habitats ^[4][5].
• Colony Type: Single-queen colonies (monogyne). Female reproductives carry the fungal cultivar from parent nest to new nest during colony foundation ^[6].
• Size & Growth:
  • Queen: Estimated 5-7mm, inferred from related Trachymyrmex species
  • Worker: Approximately 4-5mm, inferred from related Trachymyrmex species ^[1]
  • Colony: Likely several hundred workers, inferred from related Trachymyrmex species
  • Growth: Moderate, typical for fungus-growing ants
  • Development: Estimated 6-10 weeks at optimal temperature, inferred from related Trachymyrmex species (Development time is inferred from genus-level data as species-specific measurements are unavailable)
• Antkeeping:
  • Temperature: Keep at 24-28°C. These are tropical ants requiring warm, stable conditions.
  • Humidity: High humidity is essential, keep the nest substrate consistently moist but not waterlogged. Fungus-growing ants need damp conditions to support their fungal gardens.
  • Diapause: No, being a tropical species, they do not require hibernation. Maintain year-round warm conditions.
  • Nesting: Y-tong (AAC) nests or plaster nests work well. The nest must retain moisture to keep the fungal garden healthy.
• Behavior: Generally peaceful. Workers are small and slow-moving. They possess a stinger but rarely use it and pose minimal danger to keepers. As fungus growers, they spend most of their time tending to their fungal garden. Escape risk is moderate due to their small size, use standard barrier precautions.
• Common Issues: Fungal garden collapse is the primary killer, if the fungus dies, the colony will starve. Keep humidity stable and avoid contamination., Small size means escapes are possible, use fine mesh and tight-fitting lids on any outworld., Overfeeding can mold, remove uneaten organic matter promptly., Temperature drops below 20°C can slow or stop brood development and harm the fungal garden., Wild-caught colonies may carry Escovopsis fungal parasites that can devastate the garden ^[8][9].

The Fungus-Growing Lifestyle

Mycetomoellerius ruthae belongs to the Attini tribe, the famous fungus-growing ants that cultivate fungi for food. This is a mutualistic relationship where the ants provide protection and substrate for the fungus, while the fungus serves as the primary food source for larvae and a partial food source for adult workers ^[6]. The fungal cultivar is vertically transmitted, when a new queen leaves to found a colony, she carries a piece of the parent fungal garden in a special pouch called the infrabuccal pocket ^[6]. This species is part of the 'Trachymyrmex symbiosis' incorporating derived leucocoprinaceous fungi ^[7]. A critical concern in captivity is the Escovopsis fungal parasite, which has been documented infecting this species in the wild ^[8][9]. Watch for any signs of the garden turning dark, slimy, or developing unusual spores.

Feeding and Nutrition

Unlike most ants that eat insects and sugar, fungus-growing ants have a unique diet. The colony's fungal garden is their primary food source, workers feed the fungus with organic matter (typically dead plant material, caterpillar frass, or other detritus) and the fungus produces special structures called gongylidia that the ants eat. In captivity, you can feed small pieces of pre-chewed leaf matter, grain, or specialized ant food formulated for fungus growers. Some keepers offer tiny amounts of honey water or sugar water, but the main nutrition comes from the fungus. NEVER feed the ants directly, they must feed the fungus, which then feeds the colony. Avoid insect prey as a primary food source since these ants don't hunt. ^[6]

Nest Setup and Humidity

Fungus-growing ants require careful humidity management. The fungal garden needs consistent moisture to survive, too dry and the fungus dies, too wet and it drowns or molds. Y-tong (AAC) nests or plaster nests work well because they hold moisture better than acrylic. Keep the nest substrate damp but not dripping wet. A water tube attached to the nest helps maintain humidity. The distinctive chimney-like turret openings seen in wild nests ^[3] help with ventilation, in captivity, ensure some airflow to prevent stagnation while maintaining humidity. Monitor the fungal garden daily, it should look white and fluffy, not discolored or slimy.

Temperature Requirements

As a tropical species from Trinidad and Ecuador, Mycetomoellerius ruthae needs warm conditions. Keep the nest at 24-28°C for optimal brood development and fungal growth. Below 20°C, the fungus may stop growing and brood development slows dramatically. Use a low-wattage heating cable or heating mat on one side of the nest to create a gentle temperature gradient. Place the heating on TOP of the nest, not underneath, to avoid drying out the substrate too quickly. Room temperature may suffice in warm homes, but monitor with a thermometer.

Colony Foundation

When a newly mated queen starts a colony, she seals herself in a claustral chamber, this is typical for Attini ants. She carries a small piece of the parent fungal garden in her infrabuccal pocket and uses it to start a new garden ^[6]. The queen does not forage during founding, she lives off stored fat reserves while tending her tiny fungal garden. After the first workers (nanitics) emerge, they take over fungal garden maintenance and the colony grows gradually. This founding process takes several months, be patient. The first workers are typically smaller than mature workers.

Behavior and Temperament

Mycetomoellerius ruthae is a peaceful species. Workers are small, slow-moving, and unlikely to bite or sting. They spend most of their time tending the fungal garden rather than foraging aggressively. This makes them suitable for observation but less exciting than predatory ant species. They are not escape artists in the traditional sense, but their small size means they can slip through gaps that larger ants cannot. Standard barrier methods work well. The colony will expand gradually over several years.

Frequently Asked Questions

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References