Apterostigma auriculatum

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Neotropical rainforest floor from Honduras to Mato Grosso do Sul, Brazil, including Colombia, Panama, Peru, Bolivia, Ecuador, Guyana, French Guiana, Suriname, Trinidad and Tobago, and Venezuela ^[1][6][7][2]. Found under stones and logs in leaf litter on the rainforest floor ^[5][8].
• Colony Type: Likely single-queen based on small colony size of up to 50 workers, but not explicitly confirmed in research ^[5].
• Size & Growth:
  • Queen: Size data unavailable
  • Worker: Size data unavailable
  • Colony: Up to 50 workers ^[5]
  • Growth: Slow ^[5]
  • Development: Timeline unconfirmed for this species (Development likely depends on fungus garden health and temperature)
• Antkeeping:
  • Temperature: Warm tropical conditions, roughly 24-28°C, consistent with Neotropical distribution ^[1]
  • Humidity: High humidity around 70-80%, with consistently damp substrate mimicking rainforest floor conditions
  • Diapause: No diapause required, tropical species active year-round
  • Nesting: Naturalistic setup with flat stones or wood pieces covering a substrate area for the sessile fungus garden ^[5]
• Behavior: Slow-moving, solitary foragers ^[5]. Non-aggressive with minimal defense capability. Because of their small colony size and specific needs, they are vulnerable to disturbance.
• Common Issues: fungus gardens are vulnerable to Escovopsis infection, appearing as pink mold growth on the garden, 11-33% of wild colonies are affected ^[3][10], small colony size of up to 50 workers means colonies are fragile and easily wiped out by disturbance or contamination ^[5], slow growth rate requires months of stable conditions and patience before colonies reach mature size ^[5], establishing the initial fungal pellet with a new queen is difficult and often fails in captivity, queens carry fungal pellets from parent nests but success rates are low ^[9]

Fungus Garden Cultivation

Apterostigma auriculatum cultivates an ancestral type of gilled mushroom (family Lepiotaceae, G3 clade) that grows slowly compared to other attine fungi ^[3][4]. The garden sits exposed on the substrate surface under cover objects rather than being wrapped in silk, making it vulnerable to contamination ^[4]. You must provide sterile organic material to feed the fungus, such as dried leaves, flower petals, or insect frass, sterilized by boiling or baking to kill competing molds. The garden requires constant high humidity but not waterlogging. Watch for pink or cottony growths indicating Escovopsis infection, which affects 11-33% of wild colonies and can wipe out captive gardens quickly ^[3][10]. This species is the only Apterostigma that has retained the ancestral state of growing lepiotaceous cultivars rather than pterulaceous fungi ^[3].

Nest Design and Setup

In nature, these ants place their fungus gardens on the ground under large rocks, fallen logs, or inside hollow bamboo stems ^[5][8]. Replicate this in captivity using a naturalistic setup with flat stones or ceramic tiles resting on a deep layer of substrate mix (sterilized soil, leaf litter, and decaying wood). The space beneath the cover object becomes the chamber where the garden sits. Ensure the substrate stays damp but not soggy, and provide minimal ventilation to maintain humidity while preventing stagnant air. Avoid enclosed formicariums or test tubes, the ants need open access to tend the exposed garden ^[5]. They are commonly encountered under logs and rocks on the rainforest floor ^[8].

Feeding and Nutrition

The colony feeds entirely on the fungus they cultivate ^[9]. Workers forage to collect material to grow the fungus, not to eat directly. Provide your colony with sterilized organic substrates like dried leaves, small pieces of vegetables, or insect frass (sterilized waste from other insect colonies). They may also accept small amounts of sugar water or honey for energy, but the fungus garden is their primary food source. Do not feed them protein directly like mealworms, instead, provide protein-rich organic matter for the fungus to decompose. All extant attine ants obligately depend on fungal food as exclusive diet for larvae and partial diet for adults ^[9].

Colony Founding

Queens carry a fungal pellet from their parent nest when founding, which they use to start the new garden ^[9]. The exact founding behavior (whether the queen seals herself in or forages) is unconfirmed for this species. Based on other lower attine ants, founding likely requires the queen to have access to substrate and possibly to forage for garden material. Set up founding queens in small containers with damp sterile substrate and a cover object, maintaining high humidity and warmth. Success rates are typically low for fungus-growing ants in captivity. Only female reproductives carry the fungus from parent to offspring nest ^[9].

Disease and Escovopsis Management

The greatest threat to captive colonies is Escovopsis, a parasitic mold that attacks the fungus garden ^[3]. In the wild, 11% of G3-cultivar colonies show infection, with up to 33% of Apterostigma colonies affected overall ^[3][10]. If you see pink, orange, or cottony white growth spreading over the garden, remove the contaminated sections immediately with sterile tools. Maintain strict hygiene: sterilize all food items, avoid introducing unsterilized soil or plants, and ensure workers cannot track contaminants from foraging areas back to the garden. Some attines have mutualistic bacteria that produce antibiotics, but maintaining clean conditions remains essential ^[10].

Frequently Asked Questions

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References