Solenopsis carolinensis

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Eastern and southeastern United States (Arkansas, Maryland, New Jersey, North Carolina, Tennessee, Texas, Virginia, Ohio) ^[3][1]. Lives in pine forests, grasslands, shrublands, and mixed hardwood forests. Nests under bark of dead trees, in stumps, in rotten wood, and underground ^[1][5].
• Colony Type: Unconfirmed, but likely monogyne (single queen) based on typical *Solenopsis* thief ant biology.
• Size & Growth:
  • Queen: 4.08–4.20 mm ^[1]
  • Worker: 1.32–1.48 mm ^[1]
  • Colony: Unknown, no published data. Field samples can be numerically abundant (e.g., thousands of individuals in pitfall traps), but that does not necessarily reflect single‑colony size ^[6].
  • Growth: Moderate (inferred from related species – no direct data)
  • Development: Unknown, no published data for this species. (Development time has not been studied for Solenopsis carolinensis.)
• Antkeeping:
  • Temperature: Keep at room temperature (20–24 °C). This species prefers cooler soils – occurrence decreases when soil temperature and moisture increase ^[2].
  • Humidity: Keep the nest substrate slightly dry, not waterlogged. They naturally avoid wet conditions ^[2].
  • Diapause: Yes. This temperate species is found as far north as Ohio and at high elevations (2591 m in Colorado), so a winter diapause of 2–3 months at 10–15 °C is recommended ^[3][1].
  • Nesting: Natural nests are under bark, in dead wood, stumps, and underground ^[1]. In captivity, use small test tubes or Y‑tong/plaster nests with tight, dark chambers. The tiny workers prefer enclosed spaces.
• Behavior: Cryptic and secretive – workers spend most of their time underground ^[7]. They are not aggressive and will flee rather than fight. They are numerically dominant in some subterranean communities ^[6]. Escape prevention is critical due to their tiny size (1.3 mm workers can squeeze through standard mesh).
• Common Issues: tiny size means high escape risk – use fine mesh or fluon on all openings., wild‑caught colonies may carry parasites (microsporidian *Kneallhazia carolinensae* ^[9], fungal *Myrmicinosporidium durum* ^[10], or Solenopsis invicta virus‑1A ^[11]) – quarantine new colonies., sensitive to excessive humidity – keep substrate slightly dry, as they avoid wet conditions ^[2]., low visibility due to cryptic behavior – expect to see little above‑ground activity even in healthy colonies.

Housing and Nest Setup

Solenopsis carolinensis is a tiny thief ant that lives mostly underground, so it needs a dark, enclosed nest that mimics safe cavities ^[2]. Test tubes work well for founding – fill one‑third with water, plug with cotton, and keep it dark. Once the colony grows to about 50 workers, you can move them to a small Y‑tong or plaster nest, or keep them in a test‑tube setup with an outworld. Because the workers are only 1.3 mm, use fluon or very fine mesh on all openings – they can squeeze through gaps that seem impossibly small. They do not need large spaces, tight chambers make them feel secure. Avoid large open areas, they will stay hidden and may not forage properly.

Feeding and Diet

Thief ants get their name from raiding other ant colonies, but in captivity they accept small protein and sugar sources ^[8]. Offer tiny insects such as fruit flies, pinhead crickets, or pieces of mealworm. They also take sugar water, honey, or diluted syrup. Because the workers are so small, food must be cut into tiny pieces – a single fruit fly is a substantial meal. Feed every 2–3 days and remove leftovers to prevent mold. They are not aggressive foragers, place food near the nest entrance and be patient.

Temperature and Seasonal Care

Keep colonies at 20–24 °C. Research shows this species prefers cooler, drier soils – occurrence drops when soil temperature or moisture increase ^[2]. This is unusual among ants, which generally prefer warmer, wetter conditions. Avoid placing the nest in a warm room, standard room temperature is fine. In winter, provide a diapause period of 2–3 months at 10–15 °C, matching the cold winters of their natural range (e.g., Ohio, Colorado at 2591 m) ^[3][1]. Reduce feeding during diapause and keep them in a cool basement or refrigerator.

Health and Parasites

This species hosts several parasites that can harm colonies. It is a confirmed host for the microsporidian Kneallhazia carolinensae ^[9] and the fungal parasite Myrmicinosporidium durum (visible through the integument as dark spots) ^[10]. It can also carry Solenopsis invicta virus‑1A (SINV‑1A), usually when living near invasive fire ants ^[11]. Wild‑caught colonies may bring these pathogens, which can cause gradual colony decline. Quarantine any new colony for several weeks and watch for sluggish behavior, unusual mortality, or visible spores inside the workers’ bodies.

Behavior and Temperament

Carolina thief ants are cryptic and secretive. Workers are tiny (1.3 mm) and spend nearly all their time underground or hidden in leaf litter ^[7]. They are not aggressive and will retreat instead of fighting. Unlike their fire‑ant relatives, they do not have a painful sting – their venom is delivered through a stinger but is not harmful to humans. They are numerically dominant in many subterranean ant communities and can persist even when invasive fire ants are present ^[12]. This resilience makes them adaptable, but their hidden lifestyle makes them a challenge to observe.

Finding and Collecting

Solenopsis carolinensis is rarely available from ant sellers, so wild collection is the main option. They occur across the southeastern US in pine forests, grasslands, and shrublands ^[1]. Look for nests under bark of dead trees, in rotting stumps, or in soil near tree bases – they are especially common under the bark of loblolly pines (Pinus taeda) ^[5]. The best time to find dealate queens is in June, when brood and sexuals are present in the nests ^[1]. Use a soil sifter or carefully peel back bark to locate colonies. Collecting is legal in most states, but always check local regulations.

Frequently Asked Questions

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References