Strumigenys vartana

Strumigenys vartana

Strumigenys vartana is a tiny ant measuring just 2.2-2.4mm in total length, belonging to the Myrmicinae subfamily and Attini tribe ^[1]. Workers have distinctive long, narrow mandibles and a 6-segmented antenna. The head bears two pairs of erect filiform hairs, and the postpetiole disc is smooth and shining. This species is part of the Strumigenys gundlachi group, closely related to S. laevipleura but distinguished by its longer, differently shaped mandibles and the presence of short basigastral costulae ^[1].

This ant comes from cold montane forests in the northern Andes, found at altitudes between 1800 and 2530m in Colombia and Ecuador ^[1]. It belongs to a group of five Andean Strumigenys species that prefer high-elevation cold forests above 2000m where most other ants are absent. This makes them unusual among tropical ants, they're adapted to cool, damp conditions that would slow down or kill most other species.

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Northern Andes (Colombia and Ecuador), cold montane forests at 1800-2530m altitude ^[1]. Found in departments of Caldas, Quindío, Risaralda, Tolima, and Valle del Cauca in Colombia ^[2].
• Colony Type: Colony structure is unconfirmed. One specimen may represent an ergatoid (wingless reproductive), but this is uncertain.
• Size & Growth:
  • Queen: Unconfirmed, likely similar to worker size based on the gynecoid worker specimen observed ^[1]
  • Worker: 2.2-2.4mm total length, HL 0.54-0.58mm, HW 0.39-0.44mm ^[1]
  • Colony: Unknown, likely small colonies typical of Strumigenys
  • Growth: Slow, cold-adapted species develop slowly
  • Development: Unknown, likely 8-12 weeks based on typical cold-adapted Myrmicinae patterns at lower temperatures (Development is temperature-dependent, expect slower growth than tropical species)
• Antkeeping:
  • Temperature: Keep cool, 15-20°C is ideal. This species is adapted to cold Andean forests above 2000m and cannot tolerate warm conditions. Room temperature may be too warm, consider a cooling setup or keep in a cool room ^[1].
  • Humidity: High humidity required, think damp cloud forest conditions. Keep substrate consistently moist but not waterlogged. Provide a gradient from damp to slightly drier areas.
  • Diapause: Likely yes, as a cold-adapted species from high altitude, they probably need a winter rest period. However, diapause requirements are unconfirmed for this species.
  • Nesting: Prefer naturalistic setups with moist substrate. Y-tong or plaster nests can work if humidity is maintained. They likely nest in soil or rotting wood in the wild.
• Behavior: These are tiny, slow-moving ants with specialized trap-jaw mandibles. They are likely predatory on small micro-arthropods like springtails, typical of the Strumigenys genus. They are not aggressive and pose no threat to keepers. Escape prevention is critical due to their minute size, they can squeeze through the tiniest gaps. Activity level is low, they are not particularly active foragers.
• Common Issues: temperature management is critical, warm conditions will kill this cold-adapted species, escape prevention must be excellent due to their tiny 2mm size, slow growth can frustrate beginners who may overfeed or disturb the colony, high humidity requirements can lead to mold if ventilation is poor, wild-caught colonies may have parasites that are difficult to treat

Temperature and Cooling Requirements

This is the most critical aspect of keeping Strumigenys vartana. These ants are adapted to cold Andean montane forests above 2000m altitude where temperatures are cool year-round ^[1]. You must keep them between 15-20°C, this is much cooler than most ant species require. Standard room temperature (20-25°C) may be too warm and could stress or kill your colony. Consider keeping them in a cool room, basement, or use a thermoelectric cooler designed for ant keeping. Avoid any heating, these ants cannot tolerate warmth. Monitor temperatures carefully with a reliable thermometer placed near the nest.

Housing and Escape Prevention

Due to their extremely small size (workers are only 2.2-2.4mm), excellent escape prevention is essential. Use test tubes with tight-fitting plugs or Y-tong nests with fine mesh barriers. Standard fluon barriers may not work as well for ants this tiny, consider double barriers or petroleum jelly on container rims. The nest should be scaled to their minute size with small chambers and passages. Maintain high humidity within the nest while allowing for some ventilation to prevent mold. A naturalistic setup with moist soil can work well, but monitor for mold growth. ^[1]

Feeding and Diet

Strumigenys ants are specialized predators, using their trap-jaw mandibles to capture small prey. In captivity, offer tiny live prey such as springtails, small soil mites, and fruit flies. They are unlikely to accept sugar water or honey due to their predatory nature. Feed small amounts of prey 2-3 times per week, removing any uneaten prey after 24-48 hours. Do not overfeed, excess prey can mold and cause health problems. The tiny size of workers means even small prey items are substantial meals.

Humidity and Substrate Care

As inhabitants of cloud forests, these ants need high humidity. Keep the nest substrate consistently moist but never waterlogged. The substrate should feel damp to the touch. Provide a humidity gradient so ants can choose their preferred microclimate. Mist occasionally but rely on water tube reservoirs to maintain moisture over time. Good ventilation is important to prevent mold, but avoid excessive airflow that will dry out the nest. A hygrometer can help monitor humidity levels.

Behavior and Activity

Strumigenys vartana is not an active forager, expect low activity levels compared to many common ant species. Workers move slowly and deliberately, using their specialized mandibles to capture prey. They are not aggressive and cannot sting. Colonies are likely small, possibly under 100 workers at maturity. Do not disturb the colony frequently, these are subtle, secretive ants that prefer stability. Handle with extreme care due to their minute size.

Frequently Asked Questions

References