Nesomyrmex tonsuratus

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Tropical Central and South America. Found in Amazonian lowland rainforests in Ecuador (129-237 m elevation) and across Mexico, Costa Rica, Panama, Colombia, Peru, Venezuela, Brazil, and Trinidad and Tobago ^{[1][2][3][4][5]}.
• Colony Type: Unconfirmed – no data on queen number or colony structure.
• Size & Growth:
  • Queen: Size data unavailable – no body measurements recorded for queens.
  • Worker: Size data unavailable – no body measurements recorded for workers. Based on genus patterns, likely 2–5 mm, but unconfirmed.
  • Colony: Unknown – no colony size data available.
  • Growth: Unknown
  • Development: Unknown – no direct data. Tropical Myrmicinae species typically take several weeks to months at warm temperatures, but this is an estimate. (Development timeline is unconfirmed. Monitor your colony and adjust conditions based on observed growth.)
• Antkeeping:
  • Temperature: Tropical species – aim for 24–28°C. Use a heating cable on one side of the nest if room temperature is below this range. Avoid extended periods below 20°C ^[1].
  • Humidity: High humidity needed – this is a rainforest species. Keep the nest substrate consistently moist but not waterlogged. Provide a water tube for drinking. Mist the outworld occasionally and ensure good ventilation to prevent mold.
  • Diapause: Unknown – as a tropical species they likely do not require hibernation. A slight temperature reduction in winter (20–22°C) may be fine, but aim to keep it warm year-round.
  • Nesting: Likely accepts various nest types. Based on their ground-stratum classification and Amazonian habitat, they probably nest in soil or rotting wood. Use test tubes with water reservoirs, plaster nests, Y-tong blocks, or 3D-printed nests with moisture chambers. Provide leaf litter or decaying wood in the outworld to mimic their natural environment.
• Behavior: Behavior is poorly documented. Like other members of the tribe Crematogastrini, they use a modified stinger to smear venom onto enemies rather than piercing. They are likely generalist foragers that scavenge and tend aphids for honeydew. Escape risk is high – these are small ants (estimated under 5 mm), so use Fluon on test tube rims and seal all openings.
• Common Issues: limited availability – this species is uncommon in the hobby and hard to acquire., no established care protocols – most keepers will be pioneering care for this species., humidity management is critical – rainforest species are sensitive to drying out., growth and development timelines unknown, making colony management challenging., wild-caught colonies may carry parasites or diseases not yet documented in captivity.

Natural History and Distribution

Nesomyrmex tonsuratus has a broad range across the Neotropics, from Mexico (Hidalgo and Puebla) through Costa Rica, Panama, Colombia (Chocó), Peru, Venezuela, Trinidad and Tobago, Brazil, and into Ecuador ^[4][2][3][5]. The first Ecuador record came from Orellana province in the Amazonian lowlands, where specimens were collected at 129–237 m using Malaise traps and canopy fogging ^[1]. In Costa Rica inventories, the species is listed as ground stratum, but the Ecuador data show they also forage in the canopy, suggesting they are vertical foragers rather than strictly arboreal or ground-dwelling ^[6][1]. They appear to prefer pristine, humid rainforest over disturbed areas.

Identification and Morphology

You can identify Nesomyrmex tonsuratus by several features: the top of the head is smooth and shiny, and the head is notably longer than the mesosoma (body) – more than 1.1 times. The front edge of the pronotum lacks a carina (ridge), the shoulders are rounded, and the postpetiolar node is also smooth and shiny. The antennae have 11 segments ^[1]. The queen was first described in 1959,and the worker in 1975,but no body measurements are available in the literature ^[5]. Based on the genus, workers are probably 2–5 mm, but this is an estimate – actual sizes could differ.

Housing and Nesting

Since this species comes from Amazonian rainforest and is classified as ground stratum in Costa Rica, it likely prefers humid conditions with access to soil or rotting wood. For founding, a test tube with a water reservoir works well. For larger colonies, choose plaster, Y-tong, or 3D-printed nests with moisture chambers. Do not use acrylic nests – they don't hold humidity well. Add some substrate (soil or sand) and leaf litter or small pieces of decaying wood to the outworld. Keep the nest area consistently moist but avoid waterlogging to prevent drowning and mold. ^[1][6]

Feeding and Diet

No studies have looked directly at the diet of Nesomyrmex tonsuratus. Like most Myrmicinae, they are probably omnivorous generalists. Expect them to take honeydew from aphids, scavenge small dead insects, and possibly collect seeds. In captivity, offer sugar water or honey as a carbohydrate source, small live insects (fruit flies, pinhead crickets, mealworms) for protein, and a few seeds to test acceptance. Feed small amounts two to three times per week. Remove uneaten food after one day to prevent mold. Always provide fresh water.

Temperature and Seasonal Care

As a tropical species from Amazonian lowlands, Nesomyrmex tonsuratus needs warm, stable temperatures year-round. Aim for 24–28°C. If room temperature falls below 20°C, use a heating cable on one side of the nest to create a gradient. Whether they need a true winter diapause is unknown – given their origin, they probably do not. However, if your room gets significantly cooler in winter, a slight drop to 20–22°C should be fine. Active heating is safer to maintain consistent tropical conditions ^[1].

Challenges and Considerations

Keeping Nesomyrmex tonsuratus comes with several challenges. First, it's rare in the hobby and hard to obtain. Second, almost nothing is known about its specific care requirements, so you'll need to experiment and learn as you go. Third, it's a tropical rainforest species – if the nest dries out, the colony will fail, if it's too wet, mold can take over. Fourth, growth rates and colony sizes are unknown, which makes it hard to know what to expect. Beginners may find this frustrating compared to well-studied species. Finally, because it's rarely kept, there's no community knowledge base to fall back on.

Frequently Asked Questions

Report an Issue

The current care sheet is based fully on literature. See inconsistencies, or something that's incorrect? Please report here, it will be resolved after review from an admin. Contributing to the blogs tab also helps providing information, to make us be able to further improve the caresheets. Thank you for your support!

References