Strumigenys vartana

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Northern Andes (Colombia, Ecuador), cold montane forests at 1800-2530 m altitude ^[1]. Recorded from the Colombian departments of Caldas, Quindío, Risaralda, Tolima, and Valle del Cauca ^[2].
• Colony Type: Unknown. No published information on colony structure or queen number. One specimen might be an ergatoid (wingless) queen, but this is uncertain ^[1].
• Size & Growth:
  • Queen: Unknown. A gynecoid worker (possibly an ergatoid queen) was found, but no reliable queen measurements exist ^[1].
  • Worker: 2.2-2.4 mm total length ^[1].
  • Colony: Unknown. Likely small, most *Strumigenys* species keep colonies under 100 workers, but no data are available.
  • Growth: Likely slow (inferred from cold‑adapted habitat, but unconfirmed).
  • Development: Unknown. No development data exist for this species. (If kept cool (below 20 °C), development may take several weeks, but this is speculation.)
• Antkeeping:
  • Temperature: This species lives at 1800-2530 m elevation in cold Andean forests ^[1]. In captivity, you must keep it cool, likely below 20 °C. Exact temperature needs are unconfirmed. Avoid heating, standard room temperature (20-25 °C) may be too warm. Consider a cool room, basement, or a thermoelectric cooler. Use a thermometer near the nest and watch for stress.
  • Humidity: High humidity is required, think cloud forest conditions. Keep the nest substrate consistently moist but not waterlogged. Provide a gradient from damp to slightly drier areas. Ventilation must be good to prevent mold.
  • Diapause: Unknown. As a cold‑adapted high‑altitude species, it may need a winter rest period, but this has not been documented. Observe the colony’s behavior in winter.
  • Nesting: Natural nesting sites are unknown. Based on typical *Strumigenys*, they likely nest in soil, rotting wood, or leaf litter. In captivity, use a test tube or a Y‑tong/plaster nest with high moisture retention. Keep chambers small to match their size.
• Behavior: These are tiny, slow‑moving ants with trap‑jaw mandibles. They likely hunt small micro‑arthropods like springtails (typical of the genus). They are not aggressive and pose no threat to humans. Escape prevention is critical due to their 2 mm size, they can squeeze through the smallest gaps. Activity level is low, they are secretive and prefer stability.
• Common Issues: temperature too warm, this cold‑adapted species will die if kept above 20 °C for long., escape risk, their tiny size means even the smallest gap is an exit, use tight plugs and double barriers., slow growth, do not disturb the colony, overfeeding or excessive checking can stress them., mold from high humidity, balance moisture with ventilation, and remove uneaten prey quickly., lack of information, many aspects of their biology are unknown, so you must experiment carefully.

Temperature and Cooling

Keeping Strumigenys vartana cool is the most critical part of their care. They come from cold Andean forests above 1800 m ^[1]. You must keep them below 20 °C, warmer temperatures will stress or kill them. Set up the nest in a cool room, basement, or use a thermoelectric cooler. Never use a heat mat. Place a thermometer directly next to the nest and monitor daily. If you see workers becoming sluggish or dying, check temperature first.

Housing and Escape Prevention

Workers are only 2.2-2.4 mm, so they can escape through the tiniest cracks. Use test tubes with tight cotton plugs, or Y‑tong/plaster nests with fine mesh barriers. Standard fluon barriers may not hold them, try double barriers or a thin layer of petroleum jelly on the container rim. Keep the nest small and narrow to match their size. Provide high moisture in the nest but allow some air exchange to prevent mold. ^[1]

Feeding and Diet

Like other Strumigenys, this species is a predator of tiny soil arthropods. Offer live springtails, small fruit flies, or soil mites. They are unlikely to accept sugary liquids or protein jelly. Feed small amounts two or three times a week, and remove any uneaten prey after 24 hours to avoid mold. Because the ants are so small, even a single springtail is a large meal. Observing their feeding behavior is the best way to learn their preferences.

Humidity and Substrate

Cloud forests are humid, so your nest must stay moist. Keep the substrate damp (but not soaking) at all times. Create a humidity gradient by having one wet area and one drier area so the ants can choose their spot. You can use a water-filled test tube or a plaster reservoir. Watch for mold, if it appears, increase ventilation slightly and remove moldy material quickly. A hygrometer can help you track moisture levels.

Behavior and Activity

Expect a quiet, secretive colony. Workers move slowly and deliberately. They use their long mandibles to snap up prey. Activity is low, so don’t expect constant foraging. They are not aggressive, they will never attack you. Because they are so small, handle the nest with extreme care, vibrations and bright lights may stress them. Let the colony settle for weeks without disturbance. If you need to feed, do it gently and quickly.

Frequently Asked Questions

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References