Blepharidatta brasiliensis

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Central to western Amazonian region, Brazil (Acre, Amazonas, Pará, Rondônia), Colombia (Vaupés), Ecuador (Napo), and Venezuela (Amazonas). They live in moist tropical rainforest, specifically terra firme lowland rainforest ^[1][2].
• Colony Type: Polygynous colonies with 1-11 ergatoid (wingless) queens. New colonies are likely founded through colony fission rather than nuptial flights, since queens are functionally flightless ^[2]. Ergatoid queens differ from workers mainly in size and do not possess modified frontal disks ^[3].
• Size & Growth:
  • Queen: size data unavailable, ergatoid queens are slightly larger than workers but specific measurements not documented ^[1]
  • Worker: 2.5mm total length ^[1]
  • Colony: Small to medium colonies, typically 49-117 workers in most colonies but can reach up to 358 workers ^[1][2]. Average around 132 workers ^[1][2].
  • Growth: Moderate, colonies remain relatively small
  • Development: Unknown, specific development timeline has not been studied. (Brood composition is roughly 75% larvae and 25% pupae ^[1][2].)
• Antkeeping:
  • Temperature: Keep at 24-28°C as a starting point. This is an Amazonian rainforest species that prefers warm, stable conditions. Adjust based on colony activity, if they seem sluggish, slightly warmer, if they avoid the heated area, reduce temperature.
  • Humidity: High humidity is essential, these are rainforest ants. Keep the nest substrate consistently moist but not waterlogged. The substrate should feel damp to the touch. Provide a water tube as a constant moisture source.
  • Diapause: No, as a tropical species from the Amazon rainforest, they do not require hibernation. Maintain consistent year-round conditions.
  • Nesting: In nature they nest in small cavities within rotting wood or between rolled fallen leaves ^[1][2]. For captivity, a small naturalistic setup with materials like cork, small rotting wood pieces, or a carefully scaled Y-tong/plaster nest works well. The key is providing small, appropriately-sized chambers, their natural nest chambers are only about 4cm x 1.5cm ^[1][2]. They can modify their space by building walls from a mixture of soil, vegetable debris, and insect parts ^[1][2].
• Behavior: Blepharidatta brasiliensis is a nocturnal, omnivorous predator and scavenger ^[2]. Workers are active primarily at night, ceasing activity around noon and becoming active again at dusk (around 18:30) until morning (8:00) ^[2]. They are generalist predators that hunt small arthropods and other ants, and they also scavenge on dead insects ^[2]. When disturbed, workers pick up the brood and hold them in their mandibles for protection ^[1][2]. They are not particularly aggressive toward humans. However, they are skilled hunters, when catching prey, they methodically cut off legs and antennae before dragging the prey to the nest ^[1][2]. Escape prevention is critical due to their very small size (2.5mm), they can squeeze through tiny gaps.
• Common Issues: escape prevention is critical, their tiny 2.5mm size means they can slip through the smallest gaps in setups, small colony size means slower population growth compared to many common ant species, nocturnal activity pattern means you'll see most activity in evening and morning hours, don't mistake low daytime activity for problems, wild-caught colonies may have parasites that can affect survival in captivity, overfeeding can lead to mold issues in small, humid setups

Housing and Nest Setup

Because B. brasiliensis is such a tiny ant, the nest dimensions matter significantly. In the wild, they nest in small cavities within rotting branches or between rolled leaves, their chambers are only about 4cm long by 1.5cm wide ^[1][2]. For captivity, consider a small naturalistic setup with appropriately scaled chambers. A Y-tong (AAC) nest with narrow passages or a small plaster nest can work well. You can also create a naturalistic setup using small pieces of cork or rotting wood. The key is providing chambers that match their natural scale, too large and they may feel insecure.

These ants are skilled at modifying their nests. In the wild, when cavities are too large, they build walls from a mixture of soil, vegetable debris, and insect parts ^[1][2]. In captivity, this behavior suggests they can adapt to various nest materials, but they do best with some ability to manipulate their space.

Escape prevention is absolutely critical with this species. At only 2.5mm, they can squeeze through gaps that would hold back larger ants. Use fine mesh barriers, tight-fitting lids, and check all connections for tiny gaps. A thin barrier of fluon around the rim of the outworld is recommended.

Feeding and Diet

B. brasiliensis is an omnivorous predator and scavenger ^[2]. In the wild, they hunt and scavenge a wide variety of prey including spiders, diplopods, orthopteroids, beetles, flies, and especially other ant species (Camponotus, Cephalotes, Crematogaster, Dolichoderus, Ectatomma, Nesomyrmex, Pachycondyla, Pheidole, Pseudomyrmex, and Solenopsis) ^[1]. They also scavenge on dead arthropods including beetles, bees, cicadas, crickets, termites, and spiders ^[2].

One fascinating behavior observed in captivity is that they may accept plant matter, they've been baited with cream-of-rice and may collect nutrient-rich plant structures like seeds or elaiosomes ^[2]. In one study, a colony showed facultative fungivory, cropping and consuming mycelium from another ant species' fungus garden ^[2].

For captivity, offer small live prey like fruit flies, pinhead crickets, or small mealworms. They also accept dead insects and can be fed small pieces of protein-rich foods. Sugar water or honey can be offered occasionally, though they're primarily predatory. Feed small amounts 2-3 times per week and remove uneaten food promptly to prevent mold in their humid setup.

Temperature and Humidity

As an Amazonian rainforest species, B. brasiliensis requires warm and humid conditions. Keep temperatures in the range of 24-28°C as a starting point. Monitor your colony's behavior, if workers are clustered near a heat source, they may want it warmer, if they avoid the heated area, reduce temperature slightly.

High humidity is essential. These ants live in the moist Amazon rainforest and will not tolerate dry conditions. Keep the nest substrate consistently moist but not waterlogged. The substrate should feel damp to the touch. A water tube attached to the nest provides a constant source of humidity. However, balance humidity with adequate ventilation to prevent mold growth, stagnant, overly humid air can cause problems.

Unlike temperate species, they do not require diapause or hibernation. Maintain consistent year-round conditions that mimic the stable Amazonian climate. ^[2]

Behavior and Colony Dynamics

One of the most interesting aspects of B. brasiliensis is their nocturnal lifestyle. Workers are primarily active at night, with activity ceasing around noon and resuming at dusk around 18:30, continuing through the night until morning around 8:00 ^[2]. Some workers guard the nest entrance during morning hours ^[2]. Don't be concerned if your colony seems quiet during the day, this is their natural behavior.

Their colony structure is polygynous, with multiple ergatoid (wingless) queens per colony, typically 1-11 ^[1][2]. Unlike typical ants with large winged queens, these queens are worker-like in appearance and cannot fly. New colonies are likely founded through colony fission rather than nuptial flights ^[2]. This means you won't see mating flights, instead, a group of workers and ergatoid queens may simply leave to establish a new nest.

When disturbed, workers respond by picking up the brood (larvae and pupae) and holding them in their mandibles, a protective behavior to evacuate the next generation ^[1][2]. This is a fascinating behavior to observe and indicates they're sensitive to vibrations and disturbances.

Their hunting behavior is methodical, when capturing prey (including ants much larger than themselves), workers cut off the victim's legs and antennae before dragging it back to the nest ^[1][2].

Growth and Development

B. brasiliensis colonies remain relatively small compared to many common ant species. Worker populations typically range from 49-117 workers, with some colonies reaching up to 358 workers ^[1][2]. The average colony contains around 132 workers ^[1][2]. This is a small colony size, so don't expect the massive populations you might see with species like Formica or Camponotus.

The brood composition is roughly 75% larvae and 25% pupae ^[1][2]. This high proportion of larvae suggests active reproduction. Males are encountered rarely, in one study, only two colonies had males, each with a single male ^[2].

Because colonies grow slowly and stay small, patience is key. The specific egg-to-worker development time has not been documented. The small colony size also means you won't need a large formicarium, they'll do well in appropriately scaled small setups.

Frequently Asked Questions

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References