Myrmicocrypta ednaella

Myrmicocrypta ednaella

Myrmicocrypta ednaella is a small, cryptic fungus-growing ant belonging to the tribe Attini. Workers are tiny at just 0.3 mg average body mass, with small eyes containing only 3-4 ommatidia in the longest row ^[1][2]. This species is one of the most basal members of the attine ants, the group that includes the famous leaf-cutting ants, and represents an early stage in the evolution of ant agriculture ^[3]. Found throughout the Neotropical region including Colombia, Costa Rica, Honduras, and Panama, these ants nest in the ground and cultivate a specific fungus for food ^[2][4].

What makes M. ednaella particularly interesting is its ancient farming system. Unlike the more derived leaf-cutting ants that cut fresh leaves, this species collects simpler substrates like wood chips, dry plant debris, and occasional insect corpses to feed its fungal garden ^[5][6]. The queen carries the fungal cultivar in her mouth when founding a new colony, passing it down through generations ^[7]. Workers forage solitarily and feed on plant nectar and sap, which they share with nestmates through trophallaxis ^[6][8].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Neotropical region, Colombia, Costa Rica, Honduras, Panama, and Brazil. Found in lowland tropical forests, typically nesting in soil 2-100cm below the surface ^[9][4].
• Colony Type: Single-queen colonies (monogyne) with singly-mated queens. Workers are monomorphic and colonies reach several hundred individuals ^[10][9]. Queens mate only once (monandrous), giving workers very high relatedness of 0.71-0.73 ^[10][3].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Not specifically measured in primary literature, estimated based on genus patterns for basal attines
  • Worker: Very small, average body mass 0.3 mg ^[1]
  • Colony: Up to several hundred workers ^[9] (some sources indicate
  • Growth: Moderate, slower than derived attines due to smaller colony sizes
  • Development: Unconfirmed, likely 6-10 weeks based on related lower attine patterns (Development timeline not directly studied. Lower attines typically develop slower than derived leaf-cutting ants due to smaller colony sizes and simpler fungus gardens)
• Antkeeping:
  • Temperature: Keep around 24-28°C, these are tropical ants requiring warm, stable conditions. A gentle heat gradient allows them to regulate temperature.
  • Humidity: Moderate to high, fungus gardens require consistent moisture. Keep substrate damp but not waterlogged. The garden substrate (wood chips) should remain moist.
  • Diapause: No, as a tropical species, they do not require hibernation. Maintain year-round warm conditions.
  • Nesting: Ground-nesting species. Provide a naturalistic setup with soil or a plaster/acrylic nest with a chamber depth appropriate for their small size. The fungus garden needs to be suspended from the ceiling or attached to rootlets, this is critical for captive success.
• Behavior: These ants are docile and non-aggressive. Workers forage solitarily, collecting wood chips and small insects to feed their fungal garden ^[8]. They are not known to sting and pose no danger to keepers. Their tiny size (0.3 mg workers) means escape prevention is important, they can squeeze through small gaps. The most critical aspect of their behavior is the obligate dependence on their fungal cultivar: without the fungus, the colony will not survive. Workers feed on plant nectar and sap, then share food via trophallaxis with the fungus and other workers ^[6].
• Common Issues: Fungal garden collapse is the primary killer of captive colonies, maintain consistent humidity and avoid temperature swings that could harm the fungus, Tiny worker size means escape prevention must be excellent, use fine mesh barriers, Colony growth is slow compared to common ants, keepers may overfeed trying to speed up development, leading to mold problems, Obtaining the fungal cultivar is essential, wild-caught colonies bring their own fungus, but established colonies require a piece of the original garden to start new nests, Lower attine colonies remain small, do not expect the large colonies typical of Lasius or Camponotus species

The Fungus Garden: A Critical Symbiosis

Myrmicocrypta ednaella is an obligate fungus farmer, the colony cannot survive without its fungal cultivar. This is one of the most ancient forms of ant agriculture, with M. ednaella representing a basal lineage that diverged approximately 19.3 million years ago ^[6]. The ants cultivate clade 1 fungi (subclade B), which they feed primarily with wood chips, dry plant debris, leaf litter, seed fragments, and occasionally insect corpses ^[5][6]. The fungus grows in a chamber that workers tend constantly, feeding on the fungal tufts that develop. Both larvae and adults eat the fungus, it's the exclusive food for larvae and a partial diet for adults ^[7]. In captivity, you must maintain a living fungal culture. If you ever need to start a new colony from an existing one, you MUST transfer a piece of the fungus garden, the queen carries it in her mandibles when she founds a new nest ^[7].

Nest Setup and Chamber Design

In the wild, M. ednaella nests in the ground with the fungus garden chamber typically located 2-100cm below the surface ^[9]. The external nest appears as a small mound with an entrance about 2.5mm in diameter ^[11]. The queen uses her detached forewings as a platform for the incipient fungal garden during colony founding, she positions them in a cross-form with the intersection near the apical regions ^[12][11]. For captivity, a naturalistic setup with moist soil works well, or you can use a plaster nest with appropriately sized chambers. The key requirement is that the fungus garden can be suspended or attached to the ceiling of the chamber, just as they do in nature using rootlets. Chamber dimensions in wild colonies are around 34mm deep with a volume of approximately 1.08 cm³, scale your nest chambers accordingly ^[11].

Feeding and Nutrition

Adult workers feed primarily on plant nectar and sap, which they collect during foraging trips and share with nestmates through trophallaxis (mouth-to-mouth food sharing) ^[6][9]. The fungus garden is the food source for larvae. In captivity, you should provide: 1) A constant sugar source like honey water or sugar water for the workers,2) Small insects (fruit flies, pinhead crickets, small mealworms) as supplemental protein and to feed the fungus garden,3) Plant material like small leaf fragments or wood chips as substrate for the fungus. The fungus needs organic matter to grow, in the wild they use insect feces, dry plant debris, leaf-litter, and seed fragments ^[5]. Do not overfeed, as excess food leads to mold that can kill the fungal garden.

Temperature and Humidity Control

As a tropical species from Central and South America, M. ednaella requires warm conditions. Keep the nest at 24-28°C with minimal temperature fluctuations. A heating cable on one side of the nest can create a gentle gradient, but avoid direct heat on the fungus chamber. Humidity is critical because the fungus requires moisture to grow. Keep the substrate consistently damp but never waterlogged, the wood chip substrate should feel moist to the touch. Allow some variation so the ants can choose their preferred microclimate. Since they nest 2-100cm deep in the wild, they are adapted to relatively stable underground conditions. Do not let the nest dry out, as the fungal garden will die. Conversely, excessive moisture can lead to mold problems. ^[9][5]

Colony Structure and Development

M. ednaella forms single-queen colonies where the queen mates only once (monandrous), this is unusual among animals and gives workers extremely high relatedness of 0.71-0.73 ^[10][3]. Colonies remain relatively small, typically under 200 workers, though some sources indicate colonies can reach several hundred individuals ^[10][5][9]. Workers are monomorphic (all the same size) and the colony has a simple social structure. The queen carries the fungal cultivar in her mandibles when she leaves the parent nest to found a new colony, this vertical transmission of the fungus is essential for the symbiosis ^[7]. Unlike some attines, there is no evidence of multiple queens or polygynous colony structures in this species.

Defense and Health

Like other lower attines, M. ednaella has relatively simple defense mechanisms compared to the derived leaf-cutting ants. They lack the powerful stingers of more aggressive species and are generally docile. Their primary defense against fungal pathogens (like Escovopsis, a specialized parasite of attine fungus gardens) is through metapleural gland secretions containing phenylacetic acid (PAA) ^[13]. Interestingly, Escovopsis strains isolated from this species are more sensitive to PAA than those from derived attines, suggesting their defense system is effective but simpler ^[13][14]. In captivity, the biggest health threat is mold contamination of the fungus garden. Maintain clean conditions, remove uneaten food promptly, and ensure proper ventilation to prevent stagnant air that promotes mold growth.

Frequently Asked Questions

References