Temnothorax tricarinatus

Temnothorax tricarinatus

Temnothorax tricarinatus is a small, dark ant native to the western United States. Workers measure 2-2.6mm and have the characteristic 12-segmented antennae and well-developed propodeal spines typical of the genus. Their body is dark brown to brownish black with lighter leg joints and mandibles. The clypeus features a distinctive medial carina (ridge) flanked by two lateral carinae, which helps identify this species ^[1].

This species is notable for its flexible social structure, colonies can have either a single queen or multiple queens living together. They are crepuscular foragers, meaning they are most active during twilight hours, which is reflected in their relatively large eyes compared to their diurnal relatives. In the wild, they nest in small colonies of fewer than 100 workers under rocks in moist soil within open grassy areas ^[2][1].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Western United States including North Dakota, South Dakota, Idaho, Wyoming, Utah, Nevada, Arizona, Colorado, New Mexico, Nebraska, and Iowa. They inhabit open grasslands, foothill meadows, sagebrush areas, and various forest clearings. Nests are found under rocks and in moist soil in these open habitats ^[1].
• Colony Type: Facultatively polygynous, colonies can have a single queen (monogyne) or multiple queens (polygyny) ^[1].
  • Colony: Optionally polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Variable in size ^[1]
  • Worker: 2-2.6mm ^[1]
  • Colony: Fewer than 100 workers ^[1]
  • Growth: Moderate
  • Development: 6-10 weeks (estimated based on typical Temnothorax development) (Development time estimated from genus-level data, specific timing for this species has not been directly studied)
• Antkeeping:
  • Temperature: Keep at room temperature, around 20-24°C. They tolerate a range from roughly 18-26°C. A gentle temperature gradient allows workers to choose their preferred zone.
  • Humidity: Moderate to high humidity. Keep the nest substrate consistently moist but not waterlogged. These ants naturally nest in moist soil under rocks, so some dampness is important.
  • Diapause: Yes, this species is native to temperate regions with cold winters. Provide a winter rest period of 2-3 months at temperatures around 5-10°C.
  • Nesting: Y-tong (AAC) nests work well due to their small size. They also do well in naturalistic setups with flat stones over moist substrate. Avoid dry, airy nests.
• Behavior: Generally peaceful and non-aggressive. Workers are small but active foragers. They are crepuscular, meaning they show peak activity during dawn and dusk rather than full daylight. They likely supplement their diet with honeydew from aphids and scale insects, though they primarily hunt small arthropods. Escape prevention is important due to their small size, use fine mesh barriers and tight-fitting lids. They are not known for stinging and pose no danger to keepers.
• Common Issues: small size means escapes are likely without fine mesh barriers, colonies stay small (under 100 workers) so don't expect massive colonies, moisture needs are moderate, too dry causes colony decline, winter diapause is required for long-term health, wild-caught colonies may have parasites

Housing and Nest Setup

Temnothorax tricarinatus is a tiny ant, so housing needs to reflect their small size. Y-tong (acrylic cellular glass) nests work excellently because the narrow chambers are scaled to their body size. The chambers should be tight enough that workers can touch the ceiling when standing on the floor. Naturalistic setups also work well, a flat stone placed over moist soil or plaster allows them to dig their own chambers, mimicking their natural habitat under rocks ^[1].

For the outworld, keep it simple since colonies stay small. A small container or vial works for founding colonies. As the colony grows, a modest outworld area connected to the nest is sufficient. Because of their small size, escape prevention is critical, use fine mesh (at least 0.5mm) on any ventilation holes and ensure lids fit tightly. These ants are not strong climbers on smooth surfaces, but they can squeeze through surprisingly small gaps.

Feeding and Diet

In the wild, these ants are generalist predators that hunt small arthropods supplemented by honeydew from aphids and scale insects ^[1]. In captivity, offer a varied diet: small live prey like fruit flies, pinhead crickets, or springtails are readily accepted. You can also offer sugar water or diluted honey as an energy source, though protein-rich foods should form the bulk of their diet.

Feed small amounts every 2-3 days, adjusting based on how quickly the colony consumes the food. Remove any uneaten prey after 24 hours to prevent mold. Since colonies stay small (under 100 workers), even a few fruit flies per feeding is enough. A constant supply of sugar water is optional but may help with energy, especially during colony growth periods.

Temperature and Seasonal Care

Keep your colony at room temperature, ideally around 20-24°C. This species tolerates a broader range from roughly 18-26°C, but consistency is more important than precision. A gentle temperature gradient across the nest lets workers regulate their own conditions, place a heating cable on one side of the nest if your room runs cool.

Like most temperate ants, T. tricarinatus requires a winter dormancy period. Reduce temperatures gradually in fall to around 5-10°C and maintain this for 2-3 months. During diapause, reduce food to almost nothing and keep the nest slightly moist but not wet. This rest period is important for the colony's long-term health and reproductive cycles. Resume normal temperatures in spring to trigger renewed activity and brood development. ^[1]

Colony Structure and Queen Care

This species is facultatively polygynous, meaning you may encounter colonies with either a single queen or multiple queens ^[1]. If you're starting from a founding queen, she will seal herself in a small chamber (claustral founding) and raise her first brood alone on stored fat reserves. The first workers, called nanitics, are typically smaller than mature workers.

Multiple queens can coexist in established colonies, which is unusual among many ant species. If you have a polygynous colony, avoid separating the queens unless you're experienced, they typically divide egg-laying duties peacefully. Colony growth is moderate, with mature colonies reaching under 100 workers. This is a small colony size compared to many common ant species, so don't expect massive swarms.

Behavior and Observation

Temnothorax tricarinatus is crepuscular, meaning peak activity occurs during dawn and dusk ^[2]. This is reflected in their relatively large eyes compared to strictly diurnal species. Workers are active foragers who search for small prey and tend honeydew-producing insects.

The species is generally peaceful and not aggressive toward keepers. They don't have functional stingers, so there's no pain risk. However, their small size makes them adept at escaping, always use excellent escape prevention. Watching their twilight foraging behavior is part of what makes this species interesting to keep. They are alert and quick-moving despite their tiny size.

Frequently Asked Questions

References