Paratrachymyrmex mandibularis

Paratrachymyrmex mandibularis

Paratrachymyrmex mandibularis is a small fungus-growing ant native to northern South America, where it inhabits various forest types in the Guianese region ^[1][2]. These ants belong to the tribe Attini, the remarkable group of ants that cultivate fungus for food, they don't hunt or gather food directly, but instead maintain fungal gardens that they feed with plant material and insect fragments. Workers are tiny and slender, adapted to their forest floor lifestyle. The species was previously classified as Paratrachymyrmex mandibularis but has been reclassified to Paratrachymyrmex, one of nine described species in this genus ^[3]. They can be identified by their short preocular carinae and relatively long propodeal projections compared to other Paratrachymyrmex species ^[4].

What makes this species special is its agricultural lifestyle, these ants are essentially farmers, tending fungal gardens that provide their sole food source. This makes them fundamentally different from most ant species in captivity, requiring specialized care focused on fungus health rather than direct feeding.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Northern South America, specifically documented in Guianese rainforests including Liana forest, Plateau forest, Transition forest, and Inselberg forest ^[1][2]. They are leaf-litter ants, living in the humid understory of pristine tropical forests.
• Colony Type: Colony structure is unconfirmed. As fungus-growing ants, they likely establish single-queen colonies (monogyne) but this has not been directly studied for this specific species.
• Size & Growth:
  • Queen: Estimated 5-7mm based on related Trachymyrmex species
  • Worker: Estimated 3-4mm based on related Trachymyrmex species
  • Colony: Estimated 200-500 workers based on typical Paratrachymyrmex colony sizes
  • Growth: Moderate, fungus-growing ants typically grow more slowly than generalist predators
  • Development: Estimated 8-12 weeks based on related Trachymyrmex species at optimal temperature (Development is temperature-dependent, warmer temperatures within the safe range accelerate development. The first workers (nanitics) are typically smaller than normal workers.)
• Antkeeping:
  • Temperature: Keep at 24-28°C. Fungus-growing ants need warm, stable conditions to maintain both the colony and their fungal gardens. A gentle gradient allowing workers to choose their preferred temperature is ideal ^[1].
  • Humidity: High humidity is essential, aim for 70-85%. The fungal garden requires consistent moisture. Use a well-moistured substrate but ensure good ventilation to prevent mold. The nest should have a water reservoir but not be waterlogged.
  • Diapause: Likely no true diapause. As a tropical species from northern South America, they probably do not require hibernation ^[1]. Keep temperatures stable year-round.
  • Nesting: In captivity, they do well in nests that retain moisture well, acrylic nests with gypsum or plaster cores work well, or naturalistic setups with damp soil. The key is maintaining humidity for the fungus while providing adequate ventilation.
• Behavior: These ants are peaceful and not aggressive. Workers are small and slow-moving, focused on tending their fungal gardens. They are not escape artists in the traditional sense but their small size means they can slip through small gaps, use fine mesh and tight-fitting lids. They are not known to sting and pose no danger to keepers.
• Common Issues: Fungal garden collapse is the primary risk, if the fungus dies, the colony will starve. This makes humidity control critical., Mold is a constant threat in fungus-growing ant setups. Balance humidity with ventilation to prevent fungal contamination., Overheating can kill both the colony and the fungal garden. Keep temperatures stable and avoid direct heat sources that can cause localized hot spots., Small size means escape prevention must be excellent, use fine mesh barriers and check for gaps regularly., Feeding the fungus incorrectly (too much, too little, or wrong materials) can cause fungal die-off. Research proper fungal cultivation techniques.

Understanding Fungus-Growing Ants

Paratrachymyrmex mandibularis belongs to the tribe Attini, a remarkable group of ants that have evolved an agricultural symbiosis with fungi. Unlike most ants that hunt insects or collect honeydew, these ants cultivate fungal gardens as their sole food source. The queen carries a small piece of fungal inoculum when she establishes a new colony, using it to start her garden in the founding chamber. Workers feed the fungus with plant material, insect fragments, and other organic matter they collect, then harvest the fungal hyphae for consumption. This mutualistic relationship is obligate, the ants cannot survive without their fungus, and the fungus cannot survive without the ants. Understanding this is key to keeping these ants: you are essentially keeping two organisms that must both thrive for the colony to succeed. ^[1]

Housing and Nest Setup

For Paratrachymyrmex mandibularis, you need a setup that maintains high humidity while allowing adequate ventilation. Acrylic nests with gypsum or plaster cores work well because these materials hold moisture and can be connected to a water reservoir. Alternatively, a naturalistic setup with a deep layer of damp soil allows for proper fungal growth. The outworld (foraging area) should be separate from the nest and include a small dish or platform for placing fresh plant material and insect fragments. Use a test tube or water reservoir connected to the nest to maintain humidity. For escape prevention, use fine mesh (at least 0.5mm) on all openings, these ants are tiny and can slip through standard ant farm barriers. A small colony can start in a test tube setup, but plan to move to a proper formicarium within a few months as the fungal garden grows. ^[1]

Feeding the Colony

Feeding fungus-growing ants is fundamentally different from feeding regular ants. You are not feeding the ants directly, you are feeding the fungus, which the ants then consume. Offer small pieces of fresh plant material: leaf fragments, flower petals, or bits of fruit work well. You can also offer tiny amounts of insect fragments (crushed fruit flies, small crickets, or mealworm pieces) as protein for the fungus. Place food directly on the fungal garden or in a small dish in the outworld. Remove uneaten food within 24-48 hours to prevent mold. The key is balance, too much food causes mold that can kill the fungus, while too little causes the fungal garden to shrink. Watch the fungus: it should be fluffy and white. If it turns dark or slimy, something is wrong with the conditions or feeding. Never feed them sugar water or honey, they do not consume these directly. ^[1]

Temperature and Humidity Management

Maintaining proper temperature and humidity is the most critical aspect of keeping Paratrachymyrmex. These ants come from tropical rainforests and need warm, humid conditions year-round. Keep temperatures between 24-28°C, use a heating cable on one side of the nest to create a gentle gradient, but avoid direct heat that can dry or cook the fungus. Humidity should be 70-85% in the nest area. Use a water reservoir connected to the nest and mist the nest area regularly, but allow it to dry slightly between mistings to prevent stagnant conditions. Good ventilation is essential, without it, mold will overtake the fungal garden. The goal is a humid but moving air environment, not a sealed wet box. Monitor both temperature and humidity with digital meters placed near the nest. ^[1]

Colony Development and Growth

A newly founded colony starts with a single queen and a small piece of fungal inoculum she carries. The queen seals herself in a chamber and tends the fungus until her first workers (nanitics) emerge. These first workers are typically smaller than mature workers and may take 8-12 weeks to develop from egg at optimal temperatures. Growth rate is moderate, faster than some larger ant species but slower than generalist predators. The fungal garden must expand before the colony can produce more workers. As the colony grows, the fungal garden becomes larger and more resilient to minor fluctuations in conditions. Expect the colony to remain small (under 50 workers) for the first year, with growth accelerating in subsequent years if conditions are optimal. A mature colony may reach 200-500 workers. Patience is essential, fungus-growing ants are not fast growers. ^[1]

References