Acanthostichus quadratus - "No common name widely used"
Acanthostichus quadratus is a fascinating ant species belonging to the Dorylinae subfamily, which includes army ants. While they are related to army ants, they don't exhibit the typical nomadic raiding behavior. These ants are predominantly subterranean, meaning they live underground, and are rarely seen on the surface. They are known for their medium size and typically have a reddish-brown to dark brown coloration. A key feature for identifying A. quadratus is its distinctive quadrate (square-shaped) petiole, which helps distinguish it from closely related species like Acanthostichus serratulus, which has an elongated petiole. The workers have 12-segmented antennae and a large pygidium armed with finger-like setae. The queen of this species is 'subdichthadiiform', meaning she is wingless (ergatoid) but has an enlarged gaster, large eyes, and small ocelli, differentiating her from fully winged queens found in other Acanthostichus species. They are suspected to be specialized predators, primarily preying on termites.
- Difficulty: Hard
- Origin & Habitat: South America (Neotropical Region): Argentina, Bolivia, Brazil, Ecuador, Peru. in Predominantly subterranean; found under stones and wood, and in association with termite nests. They inhabit areas like secondary Atlantic Forest, often in soils with significant clay content..
- Colony Type: Monogyne (presumed, as information on polygyny is not readily available and many Dorylinae are monogyne), claustral (based on the ergatoid queen type, which typically doesn't forage during founding, though specific details are largely unknown) founding.
- Size & Growth:
- Queen: 1.83-2.1mm
- Worker: 0.99-1.49mm
- Colony: Small (hundreds of individuals have been collected in traps, indicating larger numbers subterraneanly). Slow (due to their subterranean, specialist nature and rarity in collections) growth.
- Antkeeping:
- Temperature: Specific temperature ranges are not well-documented for captive care. Given their natural habitat in tropical and subtropical South America, a stable ambient temperature between 24-28°C would likely be appropriate, mimicking their subterranean environment. Avoid extreme fluctuations..
- Humidity: High humidity is crucial due to their subterranean lifestyle. A humidity range of 70-90% should be maintained within the nest setup to prevent desiccation and mimic their natural soil environment. Consistent moisture without waterlogging is key..
- Diapause: Not required. Not specified at Not specified.
- Nesting: As subterranean ants, they require a deep, dark, and humid nest. Plaster nests, Ytong nests, or natural soil setups with significant depth would be ideal. They are known to inhabit intricate underground chambers, so a nest that allows for tunneling and depth is preferred. Avoid setups that are too open or exposed..
- Behavior: Medium (towards prey, likely low towards handler unless provoked, but information is scarce) aggressiveness.
- Common Issues: Lack of suitable food source, Incorrect humidity levels leading to desiccation or mold, Stress from inadequate nesting environment, Difficulty in monitoring colony health and growth due to cryptic nature, Mites (always a risk in humid setups).
Keeping Acanthostichus quadratus is definitely for the experienced ant keeper due to their highly specialized subterranean habits. These ants are rarely encountered in the wild, which means there's limited information on their exact care requirements. Their preference for a hidden, underground life makes it challenging to observe their natural behaviors, foraging patterns, and colony dynamics in an artificial setup. Prospective keepers should be prepared for a species that demands a very specific and stable environment.
Their diet is a significant hurdle; Acanthostichus species are suspected to be specialized termite predators. Replicating this diet in captivity can be incredibly difficult. While some success might be found with small, soft-bodied insects like flightless fruit flies or small roaches, providing a consistent and nutritionally complete substitute for termites is a major challenge. Experimentation with various protein sources would be necessary, but it's crucial to ensure they are accepted and beneficial for the colony's long-term health.
Humidity and substrate are paramount for this species. Given their natural clay-rich, subterranean habitats, maintaining consistently high humidity levels without encouraging mold growth is a delicate balance. A deep, naturalistic setup with appropriate soil composition is likely more successful than typical acrylic or Ytong formicariums. Air circulation is important to prevent mold, while still retaining the necessary moisture within the substrate.
Observing these ants will be a unique experience, as they are cryptobiotic, meaning they spend most of their lives hidden. Traditional ant farm setups with clear viewing panels might not reveal much of their activity. Consider a setup with multiple viewing angles or even a 'digging' space that can be temporarily uncovered for observation. Patience is key when keeping such a reclusive species, as visible activity will be minimal compared to surface-dwelling ants.
Due to their rarity and the lack of detailed captive care guides, ethical considerations are important. Attempting to keep Acanthostichus quadratus without thorough research and preparation could lead to colony failure. It is highly recommended to join antkeeping communities and seek advice from others who have experience with challenging or specialized ant species before acquiring a colony of A. quadratus.
