Trachymyrmex carinatus

Trachymyrmex carinatus

Trachymyrmex carinatus is a small fungus-farming ant native to the American Southwest and northern Mexico. Workers measure 0.8-1mm and have a distinctive appearance with strongly developed preocular carinae (ridges on the head) that nearly touch the frontal carinae, and a coarsely tuberculate (bumpy) first gastric tergite. Their color ranges from brownish to yellow to medium reddish-brown. This species nests in open ground, creating circular nest craters, or occasionally under stones in mountainous areas between 800-1800m elevation ^[1]. Colonies are small, typically containing fewer than 100 workers, with 1-3 underground fungus garden chambers ^[1]. Unlike leafcutter ants, these ants don't cut leaves but instead cultivate a specialized fungus for food by feeding it organic debris ^[2].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Central and southern Arizona, western New Mexico, and Mexican states of Sonora, Chihuahua and Coahuila. Found in mid-elevation habitats (800-1800m) in oak-juniper-pinyon woodlands and open exposed areas with sparse ground cover like washes and roadsides ^[1][3].
• Colony Type: Single-queen colonies (monogyne). Colonies remain small with fewer than 100 workers ^[1].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: 1.1-1.25mm ^[1]
  • Worker: 0.8-1.0mm ^[1]
  • Colony: Fewer than 100 workers ^[1]
  • Growth: Slow, small colony size indicates gradual growth
  • Development: Unknown, likely 2-3 months based on related Trachymyrmex species (Development time is unconfirmed for this specific species. Related Trachymyrmex species typically take 2-3 months from egg to worker at optimal temperatures.)
• Antkeeping:
  • Temperature: Keep at 22-26°C. These ants are from warm temperate to subtropical arid regions and prefer moderate temperatures. Avoid temperatures below 18°C or above 30°C ^[1].
  • Humidity: Keep nest substrate moderately moist but not waterlogged. In the wild, they nest in soil that can dry out between rains. Provide a moisture gradient so ants can choose their preferred humidity level ^[1].
  • Diapause: Yes, they experience a winter dormancy period in their native range (Arizona/New Mexico). Keep at 10-15°C for 2-3 months during winter ^[1].
  • Nesting: Ground-nesting species that excavates chambers. In captivity, use a naturalistic setup with soil substrate or a plaster/acrylic nest with chambers. They need enough depth to accommodate 1-3 fungus garden chambers, with the shallowest chamber at about 5cm depth in the wild ^[1].
• Behavior: Peaceful and non-aggressive. These ants are fungus farmers, they cultivate a specific fungal cultivar (Clade-B fungus) for nutrition rather than foraging for insect prey ^[4]. Workers are small and slow-moving. They do not sting and pose no danger to keepers. Escape risk is moderate due to their small size, use standard barrier methods ^[1].
• Common Issues: Fungus garden maintenance is critical, the colony depends entirely on their fungal cultivar for food, which can die if too dry or too wet, Small colony size means slow population growth, don't expect rapid expansion, Winter dormancy is required for long-term colony health, skipping hibernation can weaken colonies, Nests can flood easily given their small size, use appropriate water reservoir sizes in test tube setups, Very small workers (under 1mm) can escape through standard barrier setups, fine mesh may be needed

Fungus Garden Care

Trachymyrmex carinatus belongs to the group of 'higher-attine' fungus-farming ants that cultivate Clade-B fungi for food ^[4]. Unlike leafcutter ants that cut fresh vegetation, these ants feed their fungus decomposing organic matter. In captivity, you must maintain a healthy fungal garden. The fungus appears as a white, cottony mass in the nest chambers. Keep the fungus moist but not waterlogged, if it turns dark or slimy, it's too wet. If it turns brown and dry, it's too dry. Feed the colony small pieces of dead leaves, grass, or other plant matter, and the ants will process this to feed their fungus. Never feed the ants protein foods like insects, their digestive system is specialized for fungus nutrition alone ^[2].

Feeding and Diet

As obligate fungus farmers, Trachymyrmex carinatus does not eat typical ant foods like sugar water, honey, or insects. Their entire diet comes from the fungal cultivar they cultivate ^[2]. Provide the colony with small pieces of dead plant material, dried leaves, grass clippings, flower petals, or small bits of wood. Place this material near the nest entrance and workers will carry it into the fungus garden chamber. Remove any uneaten plant material after a few days to prevent mold. The amount needed is small given their tiny colony size. Do not offer protein sources like mealworms, crickets, or honey, these can harm the fungus and the ants cannot digest them properly.

Temperature and Seasonal Care

Keep the nest area at 22-26°C. These ants come from the warm, arid regions of the American Southwest where temperatures fluctuate between hot days and cool nights. They can tolerate brief periods outside this range but prolonged cold or heat will harm the colony. During winter (roughly November-February in the Northern Hemisphere), reduce temperature to 10-15°C to simulate hibernation. This winter dormancy is important for colony health and may trigger reproductive behavior in spring ^[1]. Do not feed the colony during hibernation, keep them cool and quiet. Resume normal temperatures and feeding in spring.

Nesting Setup

Trachymyrmex carinatus is a ground-nesting species that excavates 1-3 fungus garden chambers in soil, with the shallowest chamber typically only 5cm beneath the surface ^[1]. In captivity, a naturalistic setup with a soil-filled container works well. Use a mixture of sandy soil and clay to allow for excavation while maintaining structure. Alternatively, a plaster or acrylic nest with narrow chambers can work, but ensure the chambers are not too large for such a small species. Keep the nest dark, these ants prefer dark, humid chambers for their fungus gardens. A small water reservoir connected to the nest area helps maintain humidity without flooding.

Behavior and Colony Dynamics

This is a peaceful, slow-moving ant species. Colonies remain small with typically fewer than 100 workers ^[1]. Workers are tiny (under 1mm) and spend most of their time tending the fungus garden. Mating flights occur near dawn on mornings following summer rains, this is the only time you'll see winged reproductives ^[1]. The colony structure is simple: one queen, workers, brood, and the fungal cultivar. There are no soldiers or major workers. Because colonies stay small, they are best suited for observation rather than impressive display. They are not aggressive and do not sting, making them safe for handling, though their small size makes this impractical.

Frequently Asked Questions

References