Acromyrmex atrina

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Brazil, Neotropical region, documented in eucalyptus plantations ^[2][1].
• Colony Type: Unconfirmed, specific colony structure has not been studied for this species.
• Size & Growth:
  • Queen: Size data unavailable, inferred from Acromyrmex genus to be roughly 8-12mm
  • Worker: Size data unavailable, inferred from Acromyrmex genus to be roughly 3-7mm
  • Colony: Likely reaches several hundred to thousands of workers based on related leafcutters
  • Growth: Moderate to Fast once fungus garden establishes
  • Development: Unconfirmed, likely 6-10 weeks based on tropical Acromyrmex patterns (Timeline depends on fungus garden health and temperature)
• Antkeeping:
  • Temperature: 24-28°C as a tropical species, use a heating gradient and adjust based on activity levels
  • Humidity: High humidity around 80% with excellent ventilation to prevent fungus mold
  • Diapause: No, tropical species that remains active year-round
  • Nesting: Requires specialized fungus garden chambers with damp nest material and good airflow
• Behavior: Active foragers that cut plant material to feed their fungus gardens, can be defensive and will sting when disturbed. Workers process vegetation into pulp for the fungus rather than eating it directly.
• Common Issues: fungus garden collapse from incorrect humidity or contamination kills the colony., mold outbreaks in the nest from poor ventilation or stagnant air., this species is parasitized by inquiline ants, watch for unwanted guests in the colony., small worker size means excellent escape prevention is essential.

Fungus Garden Care

The fungus garden is the heart of your colony and requires constant attention. You must maintain damp nest material specifically for fungal growth while avoiding waterlogged conditions that cause rot. The garden needs high humidity around 80% but requires steady airflow to prevent mold. If the fungus dies, the colony starves within days. Watch for the garden turning gray, black, or developing a bad smell, healthy fungus should be white to slightly brown with a fresh mushroom scent. Never let the garden dry out completely, and avoid standing water which promotes bacterial growth. You may need to gently turn or aerate the garden material occasionally to prevent compaction. ^[1]

Feeding and Diet

These ants do not eat the leaves they collect. Instead, they chew plant material into a paste to feed their fungus, which then produces nutritious swollen structures called gongylidia that the ants consume. Offer fresh leaves, flowers, or fruit pieces daily. They have been documented in eucalyptus plantations, so eucalyptus leaves are likely accepted ^[2]. Rose petals, bramble leaves, and fresh fruit pieces are commonly used for related leafcutter species. Always ensure plants are pesticide-free. Remove old material before it molds. You can offer small amounts of oats or rice as supplemental fungus food, but fresh vegetation is essential for long-term success.

Nest Setup and Ventilation

You need a setup that accommodates the fungus garden while preventing escapes. Use a large test tube or small container with a soil or plaster base to hold moisture, connected to an outworld for foraging. The fungus chamber should be separate from the main nest area if possible. Provide ventilation holes covered with fine mesh to allow air exchange without letting ants out. Stagnant air kills fungus, too much airflow dries it out. Because of their small size, use tight-fitting lids and fine mesh barriers to prevent escapes. ^[1]

Temperature and Environment

As a Brazilian tropical species, keep them warm and stable. Start around 24-28°C and adjust based on activity levels. Use a heating cable on one side of the nest to create a gradient, but never place heat directly under the fungus garden as this causes condensation and mold. They do not need hibernation and remain active year-round. If the colony slows down significantly, check the fungus garden health rather than assuming they need cooling. ^[1]

Colony Founding

Founding behavior is unconfirmed for this specific species. Based on typical Acromyrmex patterns, queens likely found claustral (sealed in) with a piece of fungus from their parent colony. This makes founding extremely difficult in captivity. You typically need to collect a newly mated queen during her nuptial flight while she is carrying a fungus pellet, or obtain a young colony with an established garden. Starting from just a queen without fungus is likely impossible, as she cannot start a garden from scratch without the fungal inoculum. ^[1]

Defense and Temperament

Acromyrmex atrina possesses a functional stinger and can deliver mild venom when handled roughly. However, they are generally not aggressive toward humans and will only sting when directly threatened or mishandled. Their sting is mild compared to other stinging ants like fire ants. When disturbed, workers may become more active and alert, but they do not exhibit the aggressive swarming behavior seen in some other ant species. ^[1]

Frequently Asked Questions

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References