Acanthomyrmex glabfemoralis

Acanthomyrmex glabfemoralis

Acanthomyrmex glabfemoralis is a dimorphic ant from the forests of Vietnam and southern China where majors sport massive, blocky heads up to 2.56 mm wide, nearly as wide as their entire body, while minors are slender with proportionally sized heads ^[1]. These ants nest in rotting twigs, under stones, and in wood cavities on the forest floor ^[1][2]. What makes this species particularly unusual is their flexible queen system: depending on where they live, colonies either have a single normal winged queen, or instead use one or more dwarf wingless queens (called ergatoids) that look like large workers with reduced thoraxes ^[1][3]. They are opportunistic seed collectors, storing small seeds and even phasmid eggs in their nest chambers alongside insect prey ^[4][1].

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Vietnam (Lao Cai, Bac Giang, Quang Ninh, Ninh Binh, Nghe An provinces) and southern China (Guangxi, Guangdong) ^[1][5]. Found in forest floor habitats nesting in rotting wood and under stones at elevations around 900-1500 meters ^[4][1].
• Colony Type: Variable structure, either single normal queen (monogyne) or single/multiple dwarf ergatoid queens depending on population location ^[1][3].
  • Colony: Optionally polygyne
• Size & Growth:
  • Queen: Normal queens 2.00-2.33 mm head width, Dwarf queens 1.76-2.24 mm head width ^[1].
  • Worker: Majors 2.25-2.56 mm head width, Minors 1.04-1.18 mm head width ^[1].
  • Colony: Usually under 100 workers ^[3].
  • Growth: Slow
  • Development: Estimated 8-12 weeks at 24-26°C based on small colony size and related Myrmicinae patterns, but unconfirmed. (Small colony size suggests extended development time. Nanitic workers may emerge slightly faster.)
• Antkeeping:
  • Temperature: Likely 22-26°C based on tropical forest habitat ^[1][4], but specific requirements unconfirmed. Keep stable year-round.
  • Humidity: High humidity required, keep nest substrate moist but not waterlogged, similar to rotting wood conditions ^[1].
  • Diapause: Not required, tropical species from subtropical forests ^[1].
  • Nesting: Small cavities in rotting wood or under stones. Use Y-tong, plaster, or naturalistic setups with small chambers and good moisture retention ^[1][2].
• Behavior: Short foraging range of only 0.58 meters ^[4]. Majors likely serve defensive roles given their huge heads and robust mandibles ^[4]. They store seeds and phasmid eggs in nest corners ^[4][1]. Minors are tiny and can escape through minute gaps.
• Common Issues: slow colony growth requires patience, colonies remain small (under 100 workers) for extended periods ^[3]., tiny minor workers can escape through minute gaps, use fine mesh barriers and Fluon ^[1]., seed storage behavior requires providing appropriate small seeds, colonies may struggle without this natural food source ^[4][1]., high humidity needs increase mold risk if ventilation is poor.

Queen Polymorphism and Colony Structure

Acanthomyrmex glabfemoralis shows remarkable geographic variation in its reproductive strategy. In northern Vietnam populations (West Yen Tu, Chua Yen Tu, Ky Thuong, Cuc Phuong, and Pu Mat), colonies have a single normal dealate queen with a full thorax and wings ^[1][3]. However, in Van Ban and potentially other areas, colonies contain single or multiple dwarf ergatoid queens instead ^[1][3]. These dwarf queens are wingless with reduced thoraxes and come in two forms: Type A resembles normal queens but wingless, while Type B has more worker-like features including increased hairiness ^[1]. Researchers suggest this species represents a transitional stage toward the exclusive use of ergatoid queens for reproduction, a system seen in related Acanthomyrmex species ^[1]. For keepers, this means you might acquire either type, but care requirements remain similar. Colonies with multiple dwarf queens may show slightly faster initial growth, but all colonies remain small, rarely exceeding 100 workers ^[3].

Nest Preferences and Setup

In nature, these ants nest in cavities of rotting twigs and wood fragments, in cracks between stones, and under flat stones on the forest floor ^[1][2]. They prefer small, enclosed spaces with high humidity. For captive colonies, use Y-tong (AAC) blocks, plaster nests, or naturalistic setups with small chambers proportional to their size. The nest material should feel damp to the touch but not waterlogged. Provide adequate ventilation to prevent mold while maintaining humidity. Because their foraging range is only about half a meter ^[4], they do not require large outworlds, but the outworld should have secure lids and fine mesh barriers to prevent escapes from the tiny minors.

Feeding and Diet

These ants are generalist foragers with a strong preference for seeds. They collect small seeds with edible parts like elaiosomes and store them in nest chambers ^[4][1]. They also gather phasmid eggs, likely consuming the capitulum (nutritious attachment) ^[4]. Animal matter is also taken, and workers are attracted to cheese bait ^[4]. In laboratory settings, colonies have been maintained for over a year on cut pieces of mealworms and cockroaches ^[4]. Offer a variety of small seeds (such as chia, poppy, or mustard seeds) alongside protein sources. Sugar water or honey may be accepted, but seeds appear important for their natural behavior and should not be omitted.

Temperature and Seasonal Care

Coming from subtropical and tropical forests in Vietnam and southern China, these ants prefer warm, stable conditions ^[1][4]. Keep them at approximately 22-26°C year-round. They do not require hibernation (diapause), though they may benefit from a slight temperature reduction to 18-20°C during winter months if kept in temperate climates ^[1]. Avoid prolonged exposure to temperatures below 15°C. Use a heating cable on one side of the nest to create a gentle gradient, allowing the ants to self-regulate.

Behavior and Temperament

Acanthomyrmex glabfemoralis shows limited foraging behavior, with workers traveling only about 0.58 meters from the nest ^[4]. The majors with their massive heads and robust, nearly toothless mandibles likely serve as soldiers for colony defense and possibly for processing hard seeds ^[4][1]. They are not particularly aggressive but majors can deliver a noticeable bite. The minors are extremely small (body length around 1-1.5 mm) and can squeeze through tiny gaps, making escape prevention critical. They are primarily diurnal and active during warmer parts of the day.

Frequently Asked Questions

References