Myrmoteras opalinum

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Southern Thailand, Surat Thani Province, Tai Rom Yen National Park, lowland tropical forest ^[1][2]
• Colony Type: Unknown, colony structure has not been documented in the wild
• Size & Growth:
  • Queen: Undescribed, queen caste has not been documented yet
  • Worker: 3.5-4.0mm ^[1][2]
  • Colony: Unknown, only two wild colonies have ever been documented
  • Growth: Unknown
  • Development: Unconfirmed, no development data exists for this species (No captive development data exists. Estimates based on related Formicinae suggest several weeks at optimal temperature, but this is entirely speculative.)
• Antkeeping:
  • Temperature: Based on lowland tropical habitat, likely needs warm conditions around 24-28°C. Create a gentle gradient and monitor colony activity.
  • Humidity: Requires high humidity, they nest in soil in tropical lowland forest. Keep the nest substrate consistently moist but not waterlogged.
  • Diapause: Unlikely, as a tropical species from southern Thailand, they probably do not require hibernation. A slight seasonal slowdown during cooler months may occur naturally.
  • Nesting: Soil-nesting species. In captivity, use a naturalistic setup with moist soil or a Y-tong/plaster nest with good moisture retention. They prefer tight, humid chambers.
• Behavior: Behavior is unstudied in captivity. Based on genus patterns, they are likely relatively docile. Their small size (under 4mm) means escape prevention is critical, they can squeeze through standard test tube openings. Use fine mesh barriers and ensure all connections are sealed.
• Common Issues: this species is extremely rare in captivity, finding a colony is nearly impossible, no captive breeding data exists, so founding and growth are unpredictable, escape prevention is essential due to their tiny 3.5-4mm size, humidity control is critical, dry conditions will likely kill colonies, lack of species-specific care information means keepers must rely on inference from related ants

Discovery and Rarity

Myrmoteras opalinum was only described in 2013 by Bui, Eguchi, and Yamane, making it one of the more recently discovered ant species in Southeast Asia. The species is known from only two nests ever found, both in southern Thailand's Surat Thani Province within Tai Rom Yen National Park. Both colonies were collected in December 2011. This extreme rarity means wild colonies are essentially never available for antkeeping. The species gets its name from the Latin 'opalinum' meaning 'pearl-white' or 'milky, ' referring to the distinctive milk-white coloration of the coxae and femora on the middle and hind legs, a feature that makes them instantly recognizable among Indo-Chinese Myrmoteras species. ^[1][2]

Appearance and Identification

Workers of Myrmoteras opalinum are small at 3.5-4.0mm total length. The body is primarily brown with a slight reddish tinge, while the petiole and gaster (the rear segments) are darker brown. The most distinctive feature is the milk-white coloration of the middle and hind coxae and femora, with the femora of all legs being noticeably paler than the tibiae. The head and mesosoma have erect hairs, and the dorsum shows pubescence. The mandible has 8 teeth that reduce in size from the tip toward the base, with two small denticles between the first and second teeth. The frontal sulcus (a groove on the head) is faint but reaches the median ocellus. ^[1][2]

Natural Habitat and Nesting

In the wild, Myrmoteras opalinum has only been found nesting in soil within lowland tropical forest in southern Thailand. Both known colonies were collected in December 2011. The lowland forest environment suggests they prefer warm, humid conditions with stable temperatures year-round. The soil-nesting behavior indicates they need substrate moisture in captivity and likely avoid overly dry conditions. This is consistent with other Myrmoteras species, which are generally associated with moist forest floor habitats throughout their range in Southeast Asia. ^[1][2]

Housing and Care Recommendations

Since this species has never been kept in captivity (to our knowledge), all care recommendations are educated guesses based on the species' natural habitat and what we know about related ants. Provide a naturalistic setup with moist soil or a Y-tong/plaster nest that retains humidity well. Temperature should be kept in the warm range (24-28°C), consistent with their lowland tropical origin. Because they are tiny (under 4mm), excellent escape prevention is mandatory, standard test tube cotton can be too loose, and fine mesh on all openings is essential. Feed them small protein sources like fruit flies, small crickets, or other appropriately-sized prey. Sugar water or honey should be offered as well, though acceptance may need to be tested. The key principle with this species is careful observation, watch how your colony responds and adjust conditions accordingly.

Why This Species is Expert-Only

Myrmoteras opalinum is rated as Expert difficulty for several important reasons. First, they are extremely rare in the antkeeping hobby, finding a colony to acquire is nearly impossible since they have only been documented from two wild nests. Second, there is zero captive care history or established husbandry protocols for this species. Everything a keeper would need to know, from founding behavior to preferred foods to exact humidity requirements, must be inferred from limited natural history data and extrapolated from related species. Third, the conditions that keep them healthy in the wild (specific soil moisture levels, precise temperature ranges, appropriate prey types) remain largely unknown. This makes them a species for advanced keepers who understand how to adapt and experiment with care protocols rather than following established guidelines.

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