Solenopsis andina

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Known only from Cueva d'Iturbe in Jujuy, Argentina, at 3700 m in the high Andes ^[1][2]. Related specimens from Venezuela were collected in humid tropical forest at 650-1280 m elevation in forest litter ^[3].
• Colony Type: Colony structure is unconfirmed, only workers have been collected, and queens and males remain unknown ^[2]. Based on related Solenopsis, colonies are likely single‑queen, but this is speculative.
• Size & Growth:
  • Queen: Unknown, queen caste has not been described ^[2]
  • Worker: 2.56-2.75 mm total length ^[1][2]
  • Colony: Unknown, no colony size data exists
  • Growth: Unknown, no development data available
  • Development: Unknown, but estimated 4-8 weeks based on similar small Solenopsis species (This estimate is entirely speculative. Related Solenopsis species typically develop from egg to worker in 4-8 weeks depending on temperature. No direct data exists for this species.)
• Antkeeping:
  • Temperature: The 3700 m elevation suggests tolerance for cool conditions. Start around 18-22 °C and watch colony behavior. No specific thermal studies exist for this species ^[1].
  • Humidity: No specific data, but related Venezuelan specimens were found in humid tropical forest litter ^[3]. Keep the nest substrate moderately moist but not waterlogged, aim for a damp substrate with some drier areas available.
  • Diapause: Unknown, no seasonal data exists. The high‑elevation habitat likely stays cool year‑round. You could try a slight winter cooling period (around 15-18 °C) with reduced feeding, but this is speculative ^[1].
  • Nesting: No specific nesting data exists. In captivity, small test tubes or Y‑tong (AAC) nests with narrow chambers work well for their tiny size. Provide moist substrate for brood care.
• Behavior: As a thief ant, it likely hunts small invertebrates and may raid other ant nests. Workers are under 3 mm, so escape prevention is critical, they can squeeze through very tiny gaps. Aggression level is unknown, but related Solenopsis can be defensive when threatened. Like other Myrmicinae in the tribe Solenopsidini, they possess a functional stinger.
• Common Issues: only a handful of specimens exist, captive colonies are extremely difficult to start because nuptial flights have never been observed, tiny size means escapes are very likely without fine mesh barriers and tight‑fitting lids, no captive husbandry information exists, this is an expert‑only species for experienced keepers willing to experiment, queen and male castes are unknown, so you cannot reliably obtain mated queens, the high‑elevation origin suggests unusual temperature requirements that differ from typical tropical ants

Species Identification and Background

Solenopsis andina is a member of the Solenopsis nigella species complex, a group of small thief ants from South America ^[1]. It was described by Santschi in 1923 from workers collected in Jujuy, Argentina, at 3700 m elevation, one of the highest altitudes ever recorded for a Solenopsis ^[1][2]. The type specimens remain the only known individuals, making it one of the rarest ants to study.

Workers measure just 2.56-2.75 mm in total length, placing them among the smaller ants you'll keep ^[1]. You can identify them by their brown colour, large eyes with 45-55 ommatidia, and a quadrate (square‑ish) head that is only slightly longer than wide. Distinctive features include vertical striae (grooves) in front of the eyes and a well‑developed subpeduncular tooth ^[1][2]. The closely related Solenopsis nigella and Solenopsis gensterblumi occur in the same general region, and with more collections they might turn out to be the same polymorphic species ^[1].

Distribution and Habitat

Solenopsis andina is known only from its type locality: Cueva d'Iturbe, Jujuy Province, Argentina, at 3700 m elevation in the high Andes ^[1][2]. This extreme elevation is unusual for Solenopsis, most species occur at much lower altitudes. Records from Venezuela at 650-1280 m in humid tropical forest ^[3] suggest the genus can tolerate a wide elevation range when suitable microhabitats exist.

In the wild, this species would experience cool, relatively stable conditions compared to lowland tropical ants. The high Andes have significant temperature drops at night and during winter, which may influence cold tolerance. Humidity is likely moderate to high given the forest litter collection methods used for related specimens ^[3]. For captive care, aim to replicate these cool, moderately humid conditions rather than typical tropical warmth.

Housing and Nest Setup

Because workers are under 3 mm ^[1], you need appropriately scaled housing. Use test tubes with small water reservoirs or Y‑tong (AAC) nests with narrow chambers and passages. The nest material should retain moisture well, plaster or AAC setups work better than wooden formicariums for maintaining humidity. Provide a small outworld for foraging since these are active hunters.

Escape prevention is critical due to their tiny size. Standard test‑tube cotton can be insufficient, use tight‑fitting stoppers and consider applying fluon to the rim. If you use a formicarium, seal all connections and cover any ventilation holes with fine mesh (at least 0.5 mm or smaller). Gaps that would not concern larger ants can let these escape artists slip through.

Feeding and Diet

As a thief ant, Solenopsis andina probably preys on small invertebrates and may raid the brood of other ant species. In captivity, offer small live prey such as fruit flies, pinhead crickets, and small mealworms. They may also accept protein gels or crushed insects. Sugar sources like honey water or sugar water are typically accepted by Solenopsis species, though this is unconfirmed for this species.

Feed small amounts every 2-3 days and remove any uneaten prey after 24 hours to prevent mold. Because of their tiny size, even portions that seem small to you may be excessive. Watch worker behavior, if they ignore food for extended periods, reduce portion sizes. Always provide fresh water.

Temperature and Seasonal Care

The 3700 m elevation of this species ^[1] suggests they prefer cooler conditions than most tropical ants. Start with temperatures in the 18-22 °C range and observe colony behavior. If workers cluster near heat sources, slightly increase temperature, if they avoid heated areas, reduce it. Avoid overheating, this species likely has limited heat tolerance.

No specific diapause requirements have been documented. However, the high‑elevation Andean habitat experiences seasonal temperature variation, so you might consider providing a cooler period during winter (around 15-18 °C) with reduced feeding. This is speculative but matches the natural history of high‑elevation species ^[1].

Challenges and Expert‑Only Status

Solenopsis andina is NOT a species for beginners. This is an expert‑only ant for several reasons: only a handful of workers have ever been collected, the queen and male castes remain undescribed ^[2], no captive husbandry information exists, and establishing a colony may be nearly impossible without access to wild‑caught founding queens (which requires field collection in Argentina).

Before attempting to keep this species, make sure you have extensive experience with other Solenopsis or small Myrmicinae. Be prepared to experiment with temperature and humidity and to document your observations. Consider this species a research project rather than a typical pet, your observations could contribute valuable knowledge. Do not purchase this species from sellers unless you can verify that they have legitimately collected founding queens, since the species is not commercially bred.

Frequently Asked Questions

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References