Temnothorax arboreus

Temnothorax arboreus

Temnothorax arboreus is a tiny, dark brown ant species native to southern California. Workers measure just 2.5-3mm, making them one of the smaller North American Temnothorax species ^[1]. Their most distinctive feature is their arboreal lifestyle, unlike most Temnothorax which nest in soil or under stones, this species forages on tree trunks and foliage, particularly Jeffrey pine (Pinus jeffreyi) ^[1][2]. The head is shiny with weakly sculptured to smooth surfaces, and the petiole node is robust and triangular in profile ^[1]. This species belongs to the sallei-clade, a group of closely related North American acorn ants ^[1].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Southern California, USA, specifically San Diego and Riverside counties. Found in pine forest habitats at elevations around 1800m ^[1][2].
• Colony Type: Single-queen colonies (monogyne). Colony structure is typical for the genus, though detailed colony observations are limited ^[1].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Estimated 4-5mm based on genus patterns
  • Worker: 2.5-3mm (HL 0.584-0.652mm, HW 0.475-0.534mm) ^[1]
  • Colony: Likely several hundred workers based on typical Temnothorax colony sizes
  • Growth: Moderate
  • Development: Estimated 6-10 weeks based on typical Temnothorax development at room temperature (Development time inferred from genus patterns, specific data for T. arboreus not available)
• Antkeeping:
  • Temperature: Keep at room temperature (20-24°C). Being from California's mountains, they can tolerate cooler conditions than tropical species but prefer warmth ^[1].
  • Humidity: Moderate humidity preferred. As an arboreal species, they likely tolerate slightly drier conditions than ground-nesting Temnothorax. Aim for 50-60% ambient humidity with a moist nest chamber.
  • Diapause: Likely requires winter dormancy given their California mountain origin. A 2-3 month period at 10-15°C is recommended ^[1].
  • Nesting: Y-tong (AAC) nests work well for their small size. The arboreal nature suggests they prefer tight, enclosed chambers rather than open spaces. Plaster nests also suitable.
• Behavior: Generally peaceful and non-aggressive. Workers are small and active, foraging primarily on vertical surfaces (tree trunks in the wild). They are not known to sting and pose no danger to keepers. Their tiny size means escape prevention is critical, they can squeeze through standard test tube cotton if gaps exist ^[1].
• Common Issues: tiny size makes escape likely without fine mesh barriers, arboreal nature means they may have different humidity needs than typical ground-nesting ants, limited availability in the antkeeping hobby, rarely sold, winter dormancy is likely required but specifics unconfirmed, slow colony growth may frustrate beginners

Housing and Nest Setup

Temnothorax arboreus is well-suited to Y-tong (AAC) nests due to its tiny worker size and arboreal nature. The chambers should be appropriately scaled, these ants are only 2.5-3mm, so tight-fitting passages work better than open spaces ^[1]. Plaster nests also work well, as they allow you to maintain consistent humidity. Test tube setups can work for founding colonies but monitor closely for escape, their small size means they can squeeze through gaps that larger ants cannot. Avoid naturalistic setups with large open spaces, these ants prefer the security of enclosed chambers. Place the nest in a low-traffic area away from direct sunlight.

Feeding and Diet

Like other Temnothorax, this species likely accepts standard ant foods: sugar water, honey, and small protein sources. In the wild, they forage on tree trunks for honeydew and small insects. Offer a drop of sugar water or honey regularly, supplemented with tiny insects like fruit flies, pinhead crickets, or mealworm pieces. Feed protein 2-3 times per week for growing colonies. Remove uneaten food promptly to prevent mold. Being arboreal foragers, they may be more active on vertical surfaces, consider placing food on the test tube cotton or a vertical foraging area. ^[1]

Temperature and Seasonal Care

Keep your colony at room temperature (20-24°C). This species comes from California's mountain pine forests, so they can tolerate cooler temperatures than tropical species but prefer warmth for optimal brood development ^[1]. During winter, provide a dormancy period of 2-3 months at 10-15°C to simulate their natural seasonal cycle. This helps synchronize their biology with natural rhythms and promotes colony health. Reduce feeding during dormancy and keep the nest slightly cooler. Do not feed during the deepest part of winter rest.

Behavior and Observation

These are peaceful, active little ants. Workers forage individually rather than in large trails, which is typical for the genus. Their arboreal lifestyle in the wild means they're adapted to climbing on vertical surfaces, you may see them exploring test tube walls or climbing between nest chambers more than ground-nesting species. They are not aggressive and won't defend territory vigorously. Observation is rewarding because their small size reveals interesting behaviors like tending to brood and carrying food. The dark brown coloration is distinctive among North American Temnothorax ^[1].

Frequently Asked Questions

References