Tetramorium pilosum

Tetramorium pilosum

Tetramorium pilosum is a small to medium-sized ant species endemic to Sri Lanka, where it was first described from Kandy in 1893 ^[1]. Workers measure 4.1-4.5mm and have a distinctive orange-brown coloration with very long, fine hairs covering their dorsal surfaces, a key identifying feature that gives this species its name 'pilosum' (meaning hairy) ^[1]. The antennae have 11 segments, and the petiole is strongly nodiform with a convex dorsal surface ^[1]. This species belongs to the Tetramorium tortuosum species group, which is known from Sri Lanka and the Western Ghats region of India ^[2][3].

What makes T. pilosum particularly interesting is its limited distribution, it's one of the rarer Tetramorium species in the hobby, found only in Sri Lanka's forests. The closely related species T. yerburyi and T. tortuosum also occur on Sri Lanka, but T. pilosum can be distinguished by its unique petiole shape and exceptionally long body hairs ^[1]. Unfortunately, almost nothing is known about this species' biology in the wild, making it a true mystery ant for dedicated keepers.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Endemic to Sri Lanka, specifically the Kandy region in the central highlands ^[3]. This is a tropical forest species from the Indomalaya region, though its exact habitat preferences are undocumented.
• Colony Type: Unknown, the colony structure of this species has not been studied. Most Tetramorium species are monogyne (single queen), but this has not been confirmed for T. pilosum specifically.
• Size & Growth:
  • Queen: Undocumented, no queen measurements available in scientific literature
  • Worker: 4.1-4.5mm ^[1]
  • Colony: Unknown, no colony size data exists for this species
  • Growth: Unknown, no development data available
  • Development: Unknown, no direct measurements exist. Based on typical Tetramorium patterns, estimate 6-10 weeks at optimal temperature (No species-specific data available, estimates based on related Tetramorium species)
• Antkeeping:
  • Temperature: Keep at 24-28°C, this is a tropical Sri Lankan species requiring warm conditions. Room temperature is likely adequate in most homes.
  • Humidity: Moderate to high humidity preferred, Sri Lanka's central highlands are humid. Keep nest substrate slightly moist but not waterlogged.
  • Diapause: Unlikely, as a tropical species from near the equator, T. pilosum probably does not require a diapause period. However, a slight cooling period during winter months may be beneficial.
  • Nesting: No specific data exists. Based on typical Tetramorium behavior, they likely nest in soil or under stones in the wild. In captivity, a test tube setup works well for founding colonies, transitioning to a Y-tong or plaster nest as the colony grows.
• Behavior: Not documented specifically, but Tetramorium species are generally non-aggressive toward keepers and can be handled gently. Workers are active foragers that likely search for small insects and sugary substances. Their small size (under 5mm) means escape prevention is important, use fine mesh barriers. They are not known for stinging but have functional stingers as Myrmicinae.
• Common Issues: No biological data exists, keepers are essentially pioneering captive husbandry for this species, Colony growth rate is unknown, making it difficult to assess if development is normal, Temperature and humidity requirements are inferred, not confirmed, observe colony behavior and adjust, Very limited availability in the antkeeping hobby, finding colonies may be challenging, As a tropical species, sudden temperature drops could be harmful

Housing and Nest Setup

For founding colonies, a standard test tube setup works well. Fill a test tube one-third with water, plug with cotton, and place the queen in the chamber. This provides consistent humidity without flooding. Once workers have emerged (nanitics), you can maintain them in the test tube for several months while the colony establishes.

For growing colonies, transition to a Y-tong (acrylic) nest or plaster nest. These allow you to observe the colony while maintaining appropriate humidity. Keep the nest substrate slightly moist, damp but not soggy. A small water reservoir connected to the nest helps maintain stable humidity levels. Since this species is from Sri Lanka, avoid letting the nest dry out completely, but also ensure adequate ventilation to prevent mold.

Feeding and Diet

Like most Tetramorium species, T. pilosum likely accepts a varied diet including small live prey (fruit flies, pinhead crickets, small mealworms) and sugary substances (honey water, sugar water). Offer protein foods 2-3 times per week and keep a constant sugar source available.

Start with small prey items appropriate to worker size, these are small ants at 4-5mm. Live springtails or fruit flies are excellent choices. Remove uneaten prey after 24-48 hours to prevent mold. Since nothing is known about this species' specific diet preferences, experimentation is necessary, observe what your colony accepts and adjust accordingly.

Temperature and Seasonal Care

Maintain temperatures between 24-28°C year-round. This is a tropical species from Sri Lanka's central highlands, so warmth is important for colony health and brood development. Room temperature in most homes (20-24°C) may be adequate, but a small heating cable on one side of the nest can create a beneficial gradient.

Regarding diapause: as a species from near the equator in Sri Lanka, T. pilosum likely does not require true hibernation. However, slight seasonal variations may occur naturally. Some keepers report success with a minor cooling period (down to 20-22°C) during winter months, but this is optional. Do not subject this species to cold temperatures below 15°C.

Handling and Temperament

Tetramorium pilosum workers are small but not particularly aggressive. They can be handled gently with forceps or by allowing them to walk onto your hand. As Myrmicinae, they have functional stingers, but their small size means the sting is negligible to humans.

Escape prevention is important due to their small size. Use tight-fitting lids on any container and apply fluon or similar barriers to test tube openings. Fine mesh over any ventilation holes is essential, these ants can squeeze through surprisingly small gaps. When observing the colony, work over a white tray to spot any escapees quickly.

Growth and Development Expectations

Since no specific development data exists for T. pilosum, expectations are based on typical Tetramorium patterns. Queen founding typically takes 4-8 weeks for eggs to develop into workers (nanitics) at warm temperatures. Nanitics are usually smaller than full-grown workers.

Colony growth is likely moderate, expect the first few workers to emerge within 1-2 months under optimal conditions. A mature colony might reach several hundred workers, though exact maximum size is unknown. The key challenge is patience: without species-specific data, you'll need to monitor your colony's progress and adjust conditions based on observed growth rates. If workers are active and brood is developing, your conditions are likely suitable.

Frequently Asked Questions

References