Mycetophylax strigatus

Mycetophylax strigatus

Mycetophylax strigatus is a small fungus-growing ant native to southeastern Brazil and surrounding Neotropical regions. Workers measure 2.9-3.7mm and are yellowish brown to dark ferruginous in color, with distinctive scale-like hairs covering much of their body. These ants belong to the tribe Attini, meaning they cultivate fungus for food, a fascinating relationship where the ants feed their fungus specific substrate and in return harvest the fungal gongylidia (specialized food structures). Colonies are small, with documented nests containing around 30 workers, and they nest either under decaying tree bark or in simple ground nests with a small circular entrance ^[1]. This species is notable for its 'cataleptic behavior', when disturbed, workers freeze completely and remain motionless. As a primary forest specialist, they are sensitive to habitat disturbance and are rarely found in secondary growth areas ^[2].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Southeastern Brazil (Rio Grande do Sul to Rio de Janeiro states), also found in Colombia, French Guiana, and Panama. Inhabits primary Atlantic Forest and humid tropical forest zones, typically nesting under decaying tree bark or in simple ground nests ^[1][3].
• Colony Type: Likely single-queen colonies (monogyne). Documented colonies show simple nest structures with one queen and approximately 30 workers ^[1].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: 4.0-4.3mm
  • Worker: 2.9-3.7mm
  • Colony: Approximately 30 workers in documented wild colonies, colonies remain relatively small
  • Growth: Slow, fungus-growing ants typically develop more slowly than generalist ants due to the additional time needed for fungal symbiont maintenance
  • Development: Estimated 8-12 weeks based on typical Attini development patterns, specific data for this species is unavailable (Attini ants generally have longer development times than many other ant genera due to fungus cultivation requirements. Expect slower growth compared to common pet ants like Lasius or Camponotus.)
• Antkeeping:
  • Temperature: Keep at 24-28°C, these are tropical ants from southeastern Brazil that prefer warm, stable conditions. A gentle gradient allowing cooler areas around 22°C is beneficial
  • Humidity: High humidity is essential, aim for 70-80% relative humidity. These ants come from humid Atlantic Forest environments and require consistently moist substrate. Keep the fungus garden damp but not waterlogged
  • Diapause: Likely minimal or no true diapause, being a tropical species, they probably do not require hibernation. However, a slight reduction in temperature during winter months (reducing to around 20-22°C) may be beneficial to simulate seasonal slowdown
  • Nesting: Provide a naturalistic setup with moist substrate (soil or plaster) that can hold humidity. They accept both underground nests and will attach fungus to surfaces. A Y-tong or plaster nest works well, with a foraging area that allows for fungus cultivation. Keep the nest area dark and humid
• Behavior: Workers are docile and non-aggressive. The most notable behavior is their cataleptic response to disturbance, when threatened, they freeze completely and may even fall from surfaces. They are not known to sting and pose no danger to keepers. Foraging is done individually, and they cultivate their fungal symbiont in a dedicated garden chamber. Escape risk is low as they are small but not particularly agile climbers, standard barrier methods are sufficient.
• Common Issues: Fungus garden collapse, the symbiotic fungus is sensitive to drying out or mold. Maintain consistent humidity without overwatering, Small colony size, colonies remain relatively small (dozens, not hundreds of workers), so expectations for rapid growth are unrealistic, Temperature sensitivity, being tropical, they are vulnerable to cold. Keep them warm year-round, Escape through tiny gaps, while not strong climbers, their small size means they can slip through very small openings. Use fine mesh and check lid seals, Specialized diet, they require fungal substrate (typically leaf litter or other plant material) in addition to any supplemental feeding. Do not rely on sugar water alone

The Fungus-Growing Lifestyle

Mycetophylax strigatus belongs to the tribe Attini, a group of ants that have evolved a remarkable agricultural symbiosis with fungi. Unlike most ants that forage for protein and sugar sources, these ants cultivate their own food source. The queen carries a small piece of the fungal symbiont when she establishes a new colony, and this 'garden' becomes the primary food source for the colony. The fungus garden of M. strigatus consists of irregular agglomerates of small substrate pellets loosely heaped together, with visible gongylidia (specialized fungal structures rich in nutrients) that the ants harvest and feed to larvae. This means your colony needs two things to thrive: the ant colony itself AND a healthy fungal garden. The fungus requires specific substrate, typically leaf litter fragments, small pieces of plant material, or specialized fungal substrate. In captivity, you may need to experiment to find what substrate the fungus accepts best.

Housing and Nest Setup

These ants can be kept in standard test tube setups for founding colonies, but established colonies do best in naturalistic or plaster nests that can maintain high humidity. The key requirement is providing a space where the fungus garden can be maintained. A Y-tong (acrylic) nest with a water reservoir works well, as does a plaster or soil-based formicarium. The foraging area should be spacious enough for the ants to add substrate to their fungus garden. Keep the entire setup in a warm, humid location away from direct sunlight. Because they are small (under 4mm), ensure that any connections between nest chambers are not too large or the ants may get lost. A dark cover over the nest area helps simulate their natural under-bark or underground environment. ^[1]

Feeding and Nutrition

The foundation of this species' diet is their fungal symbiont. Provide small pieces of leaf litter, dead grass, or other plant material that the ants can add to their fungus garden. This is NOT optional, the fungus is their primary food source and will die without substrate to grow on. Beyond the fungus, they may accept small amounts of protein sources like fruit flies or tiny insects, but these are supplemental. Sugar water is generally NOT well accepted by fungus-growing ants, their nutrition comes from the fungal gongylidia, not from honeydew or nectar. Offer fresh plant material regularly (every 1-2 weeks) and remove any moldy or uneaten material promptly to prevent contamination of the fungus garden.

Temperature and Humidity Control

Being from southeastern Brazil's Atlantic Forest region, these ants require warm and humid conditions. Maintain temperatures between 24-28°C year-round, with a slight drop in winter being acceptable but not required. A heating cable on one side of the nest can help maintain warmth if your room temperature is below 24°C. Humidity is critical, aim for 70-80% relative humidity in the nest area. The substrate should feel consistently moist but never waterlogged. A water reservoir connected to the nest helps maintain humidity through evaporation. Monitor for condensation, some condensation is good, but excessive pooling can harm the fungus. Avoid placing the nest near air conditioning vents or in drafty areas. ^[1]

Behavior and Handling

Mycetophylax strigatus workers are notably calm and docile. When disturbed, they exhibit a fascinating 'cataleptic' response, they freeze completely and may remain motionless for extended periods, sometimes falling from surfaces. This makes them easy to observe but also means they may appear inactive or even dead when startled. They do not possess a functional stinger and pose no threat to keepers. Workers go about their tasks methodically, tending the fungus garden and foraging for substrate. They are not aggressive toward each other and colony harmony is generally good. Because they are small and slow-moving, they are not prone to escaping, standard barrier methods (fluon on rim edges) are more than adequate.

Frequently Asked Questions

References