Tetramorium ankarana

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Endemic to the Réserve Spéciale de l'Ankarana in northern Madagascar (12°54' S,49°07' E). It inhabits tropical dry forest and rainforest at elevations of 80-150 m ^[1][2]. The area has a prominent dry season (April-October) and wet season (November-March), which likely influences colony activity.
• Colony Type: Colony structure is unconfirmed. Based on typical Tetramorium patterns, likely single-queen colonies, but no direct observations exist for this species.
• Size & Growth:
  • Queen: Queen not yet described, measurements unavailable ^[1]
  • Worker: Worker total length not recorded in the literature. Head width 0.85-0.89 mm, mesosoma length 1.21-1.31 mm ^[1]
  • Colony: Unknown, only known from a handful of collected specimens ^[1]
  • Growth: Unknown, no colony development data exists for this species
  • Development: Unconfirmed, no direct data. Based on related Tetramorium species, roughly 6-10 weeks at warm temperature (around 24°C), but this is a rough inference. (Development timeline is not documented. Observing your colony will be essential to determine actual timing.)
• Antkeeping:
  • Temperature: Aim for 22-26°C as a starting range. This tropical species prefers warmth, provide a slight gradient so workers can self-regulate. Adjust based on behavior, if they cluster near heat, increase slightly, if they avoid it, lower temperature.
  • Humidity: Keep the nest substrate consistently moist but never waterlogged. This species was collected in both rainforest and dry forest, so it likely tolerates some fluctuation, but avoid letting the nest dry out completely.
  • Diapause: Unknown, as a tropical species from Madagascar, it probably does not require true hibernation. A slight temperature drop during winter months (simulating the dry season) may be beneficial, but is not necessary.
  • Nesting: Standard test tube setups are fine for founding. For established colonies, use Y-tong (AAC), plaster, or soil nests that can hold moisture. Provide a nest chamber with moist substrate and a dry outworld. Avoid acrylic nests.
• Behavior: Temperament is likely moderate, Tetramorium species are not typically aggressive but will defend their nest. Workers are very small (head width under 0.9 mm), so escape prevention is critical: use fine mesh barriers and tight-fitting lids. As a member of Myrmicinae, this ant has a modified stinger used to smear venom onto enemies (smear defense) rather than piercing. Bites or stings are not considered dangerous to humans.
• Common Issues: tiny size means escapes are likely without fine mesh barriers, no colony development data, keepers must experiment with conditions, very limited availability in the antkeeping hobby, humidity control is important, too dry and colonies may fail, too wet and mold becomes an issue, lack of documented care requirements means keepers should start conservatively and adjust based on colony responses

Origin and Distribution

Tetramorium ankarana is endemic to the Réserve Spéciale de l'Ankarana in northern Madagascar, making it one of the rarest ant species known. It was formally described in 2012 by Hita Garcia and Fisher and is known from just a few specimens collected at 80-150 m elevation ^[1]. The reserve is famous for its limestone tsingy formations and unique biodiversity. Workers were found foraging on the ground in both tropical dry forest and rainforest, suggesting the species can adapt to different moisture levels ^[1]. The type locality is 7 km southeast of Matsaborimanga.

Identification and Appearance

Workers of Tetramorium ankarana are small but distinctive within their species group. They have a dark reddish-brown color that sets them apart from their close relative Tetramorium kelleri, which is typically much lighter (whitish-yellow to brown). The head is longer than wide, the eyes are notably small, and the antennal scapes are long enough to reach the back of the head. Propodeal spines are moderately long. The body surface is heavily sculptured with a rough, wrinkled pattern on the head and upper body, while the first segment of the gaster is smooth and shiny. Numerous long standing hairs cover the whole body ^[1].

Housing and Nest Setup

Because workers are very small (head width under 0.9 mm ^[1]), excellent escape prevention is essential. Use test tubes for founding colonies, with a water reservoir that maintains humidity without flooding. The tube should have a tight-fitting cotton plug. Once the colony establishes, transfer to a formicarium. Suitable options include Y-tong (AAC) nests, plaster nests, or naturalistic setups with moist soil chambers. Provide an outworld with barriers such as fluon on the edges. Even tiny gaps in tubing or lids can allow escapes, so check all connections carefully.

Feeding and Diet

Based on typical Tetramorium feeding behavior, this species likely accepts a standard ant diet. Offer protein sources such as small insects (fruit flies, small mealworms, crickets) and provide sugar water, honey, or diluted syrup as a carbohydrate source. In the wild, they are ground foragers ^[1], so they will search for food across the outworld. Start with small portions and remove uneaten food to prevent mold. Since the species has never been kept in captivity, you may need to test different foods to see what your colony prefers.

Temperature and Humidity

As a tropical species from Madagascar, Tetramorium ankarana prefers warm conditions. Aim for 22-26°C. Provide a slight gradient (e.g., a heating cable on one side) so ants can choose their preferred temperature. For humidity, keep the nest substrate consistently moist but never waterlogged. This species was collected from both dry forest and rainforest, so it likely tolerates some variation, but avoid letting the nest dry out completely. Watch for mold (too wet) or workers clustering around the water source (too dry).

Behavior and Defense

Tetramorium ankarana is a member of the Myrmicinae subfamily. Like other Myrmicinae, it has a functional stinger. However, its tribe (Crematogastrini) uses a unique 'smear' defense: the stinger is flattened and spatulate, used to wipe venom onto enemies rather than piercing. This venom is likely mild to humans. Workers are not particularly aggressive but will defend the nest if disturbed. Because they are very small, they can easily escape through tiny gaps, so secure housing is critical. In the wild, they are ground foragers ^[1] and will search actively for food.

Colony Development Expectations

Since this species has never been documented in the antkeeping hobby, all expectations are estimates based on related Tetramorium species. Queens have not been described scientifically, so founding behavior (claustral vs. semi-claustral) is unconfirmed. Based on typical Myrmicinae patterns, expect claustral founding where the queen seals herself in and raises the first brood alone. Development from egg to first worker likely takes 6-10 weeks at optimal temperature (~24°C), but this is a rough estimate. The first workers (nanitics) will be smaller than mature workers. Colony growth will probably be moderate, Tetramorium colonies don't typically grow as large as some other genera, but well-fed colonies can reach several hundred workers over time.

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