Cheliomyrmex megalonyx

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Neotropical rainforests of northern South America (Guyana, Venezuela, French Guiana, Suriname, Brazil Pará). Found under stones and wood pieces in forest zones, including seasonally flooded dark water forests. They are primarily subterranean, nesting in hidden locations beneath surface cover ^[2].
• Colony Type: Colony structure is unconfirmed. As a Dorylinae army ant, they likely use colony fission (splitting) as their primary reproductive method, with ergatoid (wingless) queens that remain in the nest after mating.
• Size & Growth:
  • Queen: size data unavailable
  • Worker: Small for army ants, genus Cheliomyrmex workers are relatively tiny compared to other Dorylinae ^[2]
  • Colony: Colony size data unavailable, largest worker columns have been observed in the field ^[2]
  • Growth: Unknown
  • Development: Unconfirmed (Direct development data unavailable.)
• Antkeeping:
  • Temperature: Keep warm, around 24-28°C. This matches Neotropical forest floor conditions. Use a heating cable on one side of the nest to create a gentle gradient.
  • Humidity: High humidity (70-80%). These ants live in damp forest environments and need consistently moist substrate. Keep the nest substrate damp but not waterlogged.
  • Diapause: No, as a Neotropical species from regions without freezing temperatures, they do not require hibernation. They may have reduced activity during natural dry seasons rather than true diapause.
  • Nesting: Naturalistic setup works best, a deep substrate with stones and pieces of wood on top for them to nest under. Their subterranean habits mean they prefer covered, dark spaces. A Y-tong or plaster nest with a foraging area also works, but ensure darkness in the nest chamber.
• Behavior: Extremely defensive with an extremely painful sting ^[2]. They form raiding columns and are predatory on other invertebrates. When moving in columns, workers pack densely together with jaws raised, creating a protective canopy over the column ^[2]. They are primarily nocturnal or crepuscular in their raiding behavior. Escape prevention is critical, they will readily explore and find gaps, and their painful sting makes containment essential. They are aggressive hunters and will attack any invertebrate prey they encounter.
• Common Issues: escape prevention is critical, their small size and exploratory behavior means they will find any gap, painful sting makes handling dangerous, use extreme caution when opening nests, subterranean habits mean they need darkness in nest areas to feel secure, slow adoption in captivity, this species is rarely kept and husbandry is not well-established, wild-caught colonies may have parasites or be stressed from collection

Housing and Nest Setup

Cheliomyrmex megalonyx requires a setup that accommodates their subterranean and secretive nature. In the wild, they nest under stones and decaying wood in forest zones, so a naturalistic setup with a deep substrate (at least 5-10cm) works well. Place flat stones or wood pieces on top of the substrate to provide dark, covered nesting sites. You can also use a Y-tong or plaster nest with narrow chambers, but ensure the nest area remains dark, these ants are light-sensitive and will be stressed by bright illumination in their nest. The foraging area should be spacious enough for raiding columns to move through. Use a test tube setup for founding colonies, transitioning to a larger naturalistic or formicarium setup as the colony grows. ^[2]

Feeding and Diet

As army ants, Cheliomyrmex megalonyx are obligate predators. They do not collect honeydew or eat seeds, their entire diet consists of other invertebrates. Feed them a variety of small live prey including mealworms, small crickets, fruit flies, and other small insects. Prey should be small enough for workers to subdue and dismember. Unlike some ants that store food, army ants consume prey immediately and need regular feeding. Offer prey every 1-2 days, removing any uneaten remains within 24 hours to prevent mold. The large, powerful mandibles of this species suggest they can tackle prey larger than their own body size. ^[2]

Temperature and Seasonal Care

Maintain temperatures between 24-28°C, mimicking the warm Neotropical forest floor. A heating cable placed on one side of the nest creates a temperature gradient allowing ants to self-regulate. Avoid temperatures below 20°C for extended periods. Regarding seasonal changes, this species comes from regions without true winters, so they do not require hibernation. However, they may have reduced activity during natural dry seasons, you might notice slightly less activity during winter months if your room temperature drops, but this is not a diapause requirement. Keep humidity consistently high at 70-80% by misting the substrate or using a water reservoir connected to the nest. ^[2]

Behavior and Defense

This species has an extremely painful sting, one of the most painful among army ants ^[2]. When moving in columns, workers form a defensive canopy with their jaws pointed upward, creating a protective barrier against parasites like Phoridae flies that attempt to attack the column ^[2]. They are highly aggressive when defending their nest or raiding, and will readily sting any threat. Handle with extreme caution, never open nests without proper protection. They are primarily nocturnal, with raiding activity often occurring at night or during dim light conditions. Provide darkness in the nest area and minimize disturbances during daylight hours.

Colony Development and Reproduction

Army ant colonies reproduce through fission (splitting), not nuptial flights. The queen is ergatoid (wingless) and never leaves the nest after mating. When a colony reaches sufficient size, it splits into two colonies, each with its own queen. This makes colony propagation challenging in captivity, you cannot simply collect a mated queen as you would with other ants. The largest observed worker columns of this species have been impressive raiding formations ^[2]. Growth rate is unconfirmed for this species.

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