Brachymyrmex heeri

Brachymyrmex heeri

Brachymyrmex heeri is a tiny ant native to Central and South America and the Caribbean. Workers measure just 1.2-2mm with a yellowish to brown body color and distinctive nine-segmented antennae without a defined club ^[1]. This species has an unusual history, it was first described from specimens collected in a tropical orchid greenhouse in Switzerland in 1874,making it one of the first ant species documented as introduced to Europe through the plant trade ^[2][3]. Colonies are polygynous, meaning multiple queens live together in the same nest, and workers are omnivorous opportunists that frequently tend aphids for honeydew ^[1]. The species nests under stones and other objects, often in disturbed areas, and also inhabits bamboo. One fascinating trait is that some colonies produce physogastric workers, worker-like ants with greatly expanded abdomens that hang from nest ceilings, similar to honey pot ants ^[2].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Native to Central America, South America, and the Caribbean. Introduced to parts of Europe (Switzerland, Ukraine, France) and the Galapagos Islands. Found in disturbed areas, synanthropic habitats, gardens, parks, and agricultural land ^[1][2].
• Colony Type: Polygynous, multiple dealate queens occur together in nests ^[1]. However, some bamboo-nesting colonies are monogynous with a single queen ^[4], suggesting flexible colony structure.
  • Colony: Optionally polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 3-3.5mm (estimated based on genus, queen measurements not specifically documented in available literature)
  • Worker: 1.2-2mm ^[1][2]
  • Colony: Colonies can reach several hundred workers based on similar Brachymyrmex species
  • Growth: Moderate, typical for small tropical ants
  • Development: Approximately 6-8 weeks at optimal tropical temperatures (estimated based on related Formicinae species) (Development is likely faster than temperate species due to tropical origin)
• Antkeeping:
  • Temperature: Keep at 22-28°C. This is a tropical species that thrives in warm conditions. Room temperature (around 24°C) is ideal ^[2].
  • Humidity: Moderate humidity around 50-70%. They nest in soil and under stones, so they prefer slightly moist substrate but not waterlogged.
  • Diapause: No, as a tropical species, they do not require hibernation. However, they may slow down slightly in cooler temperatures.
  • Nesting: They nest under stones, in soil, and in bamboo. In captivity, a test tube setup or small formicarium with soil substrate works well. They prefer tight, enclosed spaces and will readily adopt small artificial nests.
• Behavior: Workers are small, non-aggressive, and omnivorous. They are opportunistic foragers that readily accept sugar sources (honeydew from aphids, sugar water) and protein (small insects). They are not known to sting and pose no danger to keepers. Their small size (1.2-2mm) means escape prevention is important, they can slip through tiny gaps. Workers are active foragers both on the ground and in vegetation, and they commonly tend aphids for honeydew ^[1].
• Common Issues: tiny size means escapes are likely without fine mesh barriers, colonies may be slow to establish due to small colony size at acquisition, as a tropical species, they may not tolerate temperatures below 18°C, wild-caught colonies may carry parasites that can cause colony failure, multiple queens may cause initial aggression when establishing, give them time to sort out hierarchy

Housing and Nest Preferences

Brachymyrmex heeri is a small ant that nests in soil, under stones, and in bamboo in the wild ^[1]. For captive care, a simple test tube setup works well for founding colonies. Once established, they can be moved to a small formicarium with a soil or plaster nest. They prefer tight, enclosed chambers rather than open spaces. Because of their tiny size (1.2-2mm), ensure your setup has no gaps larger than 1mm, these ants can slip through surprisingly small openings. A small outworld connected to the nest allows for feeding. They do well at room temperature (22-26°C) and do not require special heating. Keep the nest substrate lightly moist but not waterlogged.

Feeding and Diet

These ants are omnivorous opportunists. In the wild, they commonly tend aphids and scale insects for honeydew and also forage for small insects and nectar ^[1][5]. In captivity, offer a mix of sugar water or honey (for carbohydrates) and small protein sources like fruit flies, pinhead crickets, or other tiny insects. They will readily accept both sweet and protein foods. Feed them small amounts every few days, removing any uneaten food to prevent mold. Because they are so small, their food portions should be correspondingly tiny, a drop of sugar water and one or two small prey items is sufficient.

Temperature and Seasonal Care

As a tropical species from Central and South America, Brachymyrmex heeri prefers warm conditions. Keep them at 22-28°C for optimal activity and brood development. They do not require a diapause or hibernation period like temperate species. However, they can tolerate brief periods at lower temperatures and are even found in greenhouses in cooler climates like Switzerland ^[2]. If your room temperature stays above 20°C year-round, no special seasonal adjustments are needed. Avoid placing the colony near cold drafts or air conditioning vents.

Colony Structure and Behavior

This species is polygynous, meaning colonies typically have multiple queens living and reproducing together ^[1]. However, research shows some bamboo-nesting colonies have only a single queen ^[4], suggesting the species can adapt its colony structure. Workers are small (1.2-2mm), soft-bodied, and completely harmless to humans, they do not sting. They are active foragers both on the ground and in vegetation, and are known to climb plants to tend aphids. One unusual trait is the presence of physogastric workers, worker-like ants with greatly expanded abdomens that hang from nest ceilings, similar to honey pot ants. This appears to be a food storage adaptation ^[2]. The species is not aggressive and poses no threat to keepers or other ant colonies.

Escape Prevention

Due to their very small size (1.2-2mm), excellent escape prevention is essential. These tiny ants can squeeze through gaps that would hold back larger species. Use fine mesh on any ventilation holes, ensure all connections are tight-fitting, and consider using a barrier like fluon around the edges of the outworld. Test tube setups should have well-fitted cotton stoppers. Even small gaps around tubing connections can allow escapes. Check your setup regularly and seal any potential escape routes.

Frequently Asked Questions

References