Brachymyrmex delabiei

Brachymyrmex delabiei

Brachymyrmex delabiei is a tiny yellowish ant species native to the Brazilian Atlantic Forest, described in 2014. Workers are among the smallest ants in the genus, measuring just 0.30-0.43mm in Weber length, with a smooth and shiny body that distinguishes it from related species like B. brasiliensis. The species is identifiable by its five long erect hairs on the clypeus (one central, two lateral pairs) and two erect hairs each on the pronotum and mesonotum. This ant was named in honor of Dr Jacques Delabie for his contributions to ant taxonomy. Only the worker caste has been described, queens and males remain unknown. The species has been collected from three Brazilian states (Bahia, Santa Catarina, and São Paulo) using Winkler traps in pristine Atlantic Forest regions.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Brazilian Atlantic Forest in the states of Bahia, Santa Catarina, and São Paulo. Type specimens were collected in a pristine region of Tapiraí, São Paulo using Winkler traps in January 2001 ^[1][2]. This is a tropical to subtropical forest environment with high humidity.
• Colony Type: Unknown colony structure. Only worker caste has been described. Queens and males remain unknown, so monogyne/polygyne status cannot be confirmed. Based on typical Brachymyrmex genus patterns, likely single-queen colonies.
• Size & Growth:
  • Queen: Unknown, queens have not been described ^[1].
  • Worker: Workers are tiny at 0.30-0.43mm Weber length (WL), with head length 0.34-0.41mm and head width around 0.32mm ^[1][3].
  • Colony: Unknown, no colony size data available for this species.
  • Growth: Unknown, no development data exists for this recently described species.
  • Development: Unknown, no direct measurements. Based on typical Brachymyrmex patterns (small tropical ants), estimate 4-8 weeks at warm temperatures, but this is an educated guess. (No published development data exists. Related Brachymyrmex species typically develop relatively quickly in warm, humid conditions.)
• Antkeeping:
  • Temperature: Keep warm, around 24-28°C. Based on Brazilian Atlantic Forest habitat, this is a tropical environment with year-round warmth. Provide a temperature gradient so ants can choose their preferred spot.
  • Humidity: High humidity required, think damp forest floor. Keep nest substrate consistently moist but not waterlogged. Atlantic Forest environments are humid, so aim for 70-85% humidity in the nest area.
  • Diapause: Unknown for this species. Tropical ants from Atlantic Forest may not require true hibernation, but may slow down during cooler months. Monitor colony activity and adjust accordingly.
  • Nesting: In captivity, small test tubes or acrylic nests work well for these tiny ants. Provide moist substrate (soil or plaster) to maintain humidity. Given their small size, ensure chambers and passages are appropriately scaled.
• Behavior: These are tiny, relatively docile ants. They are not aggressive and likely forage individually or in small groups. Their small size (under 0.5mm) makes escape prevention critical, they can squeeze through standard barriers. They are generalist feeders based on typical Brachymyrmex diet. Activity level is likely moderate, they forage actively but not frantically. Like most Brachymyrmex, they are likely nocturnal or crepuscular to some degree.
• Common Issues: escape prevention is critical due to their tiny size, use fine mesh and tight-fitting barriers, no published care information exists, this is a recently described species with only workers known, queen and male castes are unknown, cannot confirm founding type or colony structure, slow colony growth is typical for tiny ants with unknown development timelines, wild-caught colonies may have parasites or diseases since this species has never been kept in captivity

Species Identification and Discovery

Brachymyrmex delabiei is a recently described species, only named in 2014 by Ortiz and Fernández. It was identified primarily by its unique morphological features: the presence of tumuliform (bulging) metathoracic spiracles, five long erect hairs on the clypeus arranged in a specific pattern, and its entirely smooth and shiny yellowish body. The species honors Dr Jacques Delabie, a prominent ant taxonomist who has supported many researchers working in the Neotropics. Only the worker caste has been collected and described, the queen and male castes remain unknown, which is unusual for ant species in captivity. This means we have no direct information about how this species founds colonies or reproduces. ^[1][2]

Natural Habitat and Distribution

This species is known only from Brazil, specifically from three states in the Atlantic Forest region: Bahia, Santa Catarina, and São Paulo. The type specimens were collected in Tapiraí, São Paulo, in a pristine region of Brazilian Atlantic Forest using Winkler traps (a method that sifts leaf litter to collect tiny arthropods). This habitat is characterized by high humidity, dense forest cover, and warm tropical to subtropical temperatures year-round. The Atlantic Forest is one of the most biodiverse ecosystems in the world but is also highly threatened, making pristine collection locations relatively rare. The fact that this species has only been collected a few times suggests it may be uncommon or difficult to detect due to its tiny size. ^[1][3]

Size and Morphology

Brachymyrmex delabiei workers are among the smallest ants in the Brachymyrmex genus, with Weber lengths (a standard ant measurement from the front of the pronotum to the tip of the gaster) ranging from just 0.30mm to 0.43mm. Their head length is 0.34-0.41mm and head width around 0.32mm. The body is entirely smooth and shiny, which distinguishes it from the similar B. brasiliensis which has a more textured appearance. They have five distinctive long erect hairs on the clypeus (the face shield), two erect hairs on the pronotum, and two on the mesonotum. Their scapes (the first segment of the antennae) surpass the posterior margin of the head. The species is monomorphic, meaning all workers are roughly the same size with no major worker sub-castes. ^[1][3]

Housing and Nest Setup

For such tiny ants, housing requires careful attention to scale. Test tubes work well for founding colonies, use a small water reservoir with a cotton plug, keeping the tube consistently moist but not flooded. For established colonies, acrylic nests or small formicaria with appropriately sized chambers work well. The key requirements are: maintain high humidity (70-85%), keep the nest warm (24-28°C), and ensure the chambers are small enough that the ants can easily navigate. Because of their minute size, escape prevention is critical, standard cotton plugs may not be sufficient. Use fine mesh barriers and check for any gaps in your setup regularly. A layer of substrate (soil or sand) helps them feel secure and allows for natural tunneling behavior.

Feeding and Diet

While no specific feeding studies exist for B. delabiei, Brachymyrmex species are generally omnivorous and opportunistic. They likely feed on honeydew (the sugary secretion from aphids and scale insects), small insects, and nectar. In captivity, you can offer: sugar water or honey (very small amounts since they are tiny), tiny live prey like springtails or fruit fly larvae, and occasionally small insects. Feed small amounts every few days and remove any uneaten food to prevent mold. Given their small size, even a single fruit fly is a substantial meal. Observe what your colony accepts and adjust accordingly.

Temperature and Seasonal Care

As a Brazilian Atlantic Forest species, B. delabiei requires warm, stable temperatures. Aim for 24-28°C in the nest area, with a slight gradient so ants can move to warmer or cooler spots if needed. Room temperature may be sufficient if your home stays in this range, otherwise use a heating cable or mat on one side of the nest. High humidity is essential, the Atlantic Forest is a humid environment. Keep the nest substrate moist but not waterlogged. Regarding diapause (winter rest): tropical ants often don't require true hibernation, but may slow down during cooler months. Monitor your colony's activity and reduce feeding slightly if they become less active. Do not let temperatures drop below 18°C for extended periods.

Frequently Asked Questions

References