Paratrachymyrmex irmgardae

Paratrachymyrmex irmgardae

Paratrachymyrmex irmgardae is a small fungus-growing ant species native to northern Colombia. Workers are typical Attini-sized (likely 3-5mm based on genus patterns), with distinctive morphological features including smooth mandibles lacking prominent teeth and a gaster with minimal hair-tubercles. This species belongs to the 'higher-attine' group of ants that cultivate specialized fungi for food, they are not leaf-cutters but instead feed their fungal gardens with small plant fragments and organic matter ^[1]. The species is only known from Colombia, particularly the Sierra Nevada de Santa Marta region and surrounding areas in La Guajira and Magdalena departments ^[2][3]. As one of nine described species in Paratrachymyrmex, these ants represent an interesting option for antkeepers interested in fungus-culturing species ^[4].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Northern Colombia, specifically the Sierra Nevada de Santa Marta region, La Guajira, Magdalena, and Cesar departments. They inhabit tropical dry forest areas at elevations around 250-150m ^[3]. The region features warm, seasonally dry conditions with temperatures typically in the mid-to-high 20s°C.
• Colony Type: Likely monogyne (single queen colonies) based on typical Attini patterns. Colony size is unknown but likely moderate, similar Attini species typically reach a few hundred workers.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Unknown, estimated 5-7mm based on genus patterns for Paratrachymyrmex
  • Worker: Estimated 3-5mm based on typical Attini worker size
  • Colony: Unknown, likely several hundred workers based on related species
  • Growth: Moderate, fungus cultivation adds time to colony development
  • Development: Estimated 8-12 weeks at optimal temperature based on typical Attini development (Fungus-growing ants typically have slightly longer development times than non-cultivating species because the queen must establish the fungal garden before workers can be raised)
• Antkeeping:
  • Temperature: Keep at 24-28°C. As a tropical Colombian species, they need warm conditions. A heating cable on one side of the nest creates a suitable gradient
  • Humidity: Moderate to high humidity (60-80%). Keep the nest substrate consistently moist but not waterlogged. Fungus gardens need moisture but can be damaged by oversaturation
  • Diapause: No, as a tropical species from Colombia, they do not require hibernation. Keep them warm year-round
  • Nesting: Y-tong (AAC) nests or plaster nests work well. These ants need a fungal garden chamber. Avoid overly wet setups that could damage the fungus. Provide a small outworld for foraging
• Behavior: Generally peaceful and non-aggressive. Like other Attini ants, they are not territorial outside their nest and focus on fungus cultivation. Workers are small and slow-moving. Escape risk is moderate, use standard barrier methods but they are not particularly adept escape artists. They forage for small organic particles to feed their fungus, not large prey.
• Common Issues: fungal garden failure is the primary risk, improper humidity or contamination can kill the culture, tropical species are sensitive to temperature drops, keep consistently warm, limited availability makes this species difficult to acquire, slow growth compared to non-fungus-cultivating species may frustrate beginners, wild-caught colonies may carry fungal pathogens that fail in captivity

Fungus Cultivation - The Key to Their Care

Paratrachymyrmex irmgardae belongs to the tribe Attini, a group of ants that have evolved a mutualistic relationship with cultivated fungi. Unlike leaf-cutter ants (Atta and Acromyrmex), these 'higher-attine' ants do not cut large leaf pieces. Instead, they collect small organic fragments, plant matter, and insect remains to feed their fungal gardens ^[1]. This is the most critical aspect of their care, the fungal colony is the actual food source, not the material you provide. The ants feed on special gongylidia produced by the fungus. In captivity, you can provide small pieces of leaves, grass, flower petals, or other organic matter. Some keepers also offer tiny amounts of insect protein. The fungus requires consistent moisture and stable temperatures to thrive. If the fungal garden dies, the colony will starve regardless of how much food you provide.

Nest Setup and Housing

For this species, a Y-tong (AAC) nest or plaster formicarium works well. The nest should have a dedicated chamber for the fungal garden that stays consistently moist without becoming waterlogged. Provide a small outworld for foraging where you can place organic material. Unlike some ants, they do not need large spaces, a modest setup is fine. Escape prevention is straightforward as they are not particularly agile or determined escape artists, though standard barriers (Fluon, talcum powder) are always recommended. The nest material should hold moisture well, many keepers use a mixture of soil and other substrates that can support fungal growth.

Temperature and Humidity

As a tropical species from Colombia, Paratrachymyrmex irmgardae needs warm conditions year-round. Keep the nest at 24-28°C, with a slight gradient allowing workers to choose their preferred temperature. A heating cable on one part of the nest can provide this gradient. Temperature drops below 20°C can stress the colony and damage the fungal garden. For humidity, aim for 60-80% relative humidity in the nest. The substrate should feel consistently moist but never soggy. Overly wet conditions cause fungal rot, while dry conditions kill the fungus. Monitor the fungal garden's health, a healthy fungus is white and growing, while a dying fungus turns dark or stops growing. ^[3]

Feeding and Nutrition

The primary food is the fungal garden, not direct prey. Provide small organic materials for the ants to cultivate their fungus: tiny leaf fragments, grass clippings, flower petals, seed husks, or small pieces of fruit. Some keepers report success offering tiny amounts of protein like small insects or boiled egg, but this should be given sparingly and removed if not consumed. Do not offer large prey items, these ants are not effective predators. Sugar water is generally not needed and may harm the fungal garden if spilled. The key is providing a steady, small supply of organic matter rather than large feeding events. Observe how quickly the ants process what you provide and adjust accordingly.

Colony Development and Growth

Colony growth in fungus-growing ants follows a specific pattern. A newly mated queen seals herself in a chamber and begins cultivating a small fungal pellet. She feeds the fungus with her own metabolic resources until the first workers emerge (nanitics). These workers then take over foraging for organic material to expand the fungal garden. Development from egg to worker likely takes 8-12 weeks at optimal temperature, though this is estimated based on related Attini species. Colonies grow moderately fast once established, but the need to build and maintain a fungal garden means growth is slower than comparable-sized non-cultivating ants. Maximum colony size is unknown but likely reaches several hundred workers based on related species.

Frequently Asked Questions

References