Rotastruma epispina

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Known only from Kampong Thom Province, Cambodia (12°38'N,105°16'E). Found in regrowth forest, nesting in dead twigs on lower vegetation ^[1].
• Colony Type: Polygynous (multiple queens), the type colony contained two dealate queens ^[1].
• Size & Growth:
  • Queen: 3.88-4.01 mm total length ^[1]
  • Worker: 3.25-3.40 mm total length ^[1]
  • Colony: Unknown, only the type colony has been documented ^[1]
  • Growth: Unknown
  • Development: Unconfirmed, no development data exists for this species (Development timeline has not been studied. Related Myrmicinae of similar size typically develop from egg to worker in 6-10 weeks at optimal temperatures.)
• Antkeeping:
  • Temperature: Unknown for this species. Based on its Cambodian origin (tropical climate), aim for warm conditions around 24-28°C. Related Southeast Asian Myrmicinae suggest they prefer stable, warm temperatures with moderate humidity.
  • Humidity: Unknown, the natural habitat in regrowth forest suggests moderate to high humidity. Keep nest substrate lightly moist but not waterlogged. Provide a moisture gradient so ants can choose their preferred level.
  • Diapause: Unlikely, being a tropical species from Cambodia, they probably do not require a true diapause. However, a slight reduction in temperature during winter months may be beneficial.
  • Nesting: In nature, they nest in dead twigs on lower vegetation ^[1]. In captivity, a small test tube setup or Y-tong nest with appropriately scaled chambers would work well. The tiny worker size (3.3 mm) means chambers should be small and tight-fitting. Avoid large, open spaces.
• Behavior: Behavior is unstudied in captivity. Based on genus placement in Myrmicinae and their small size, they are likely secretive and slow-moving. Workers probably forage individually for small prey and honeydew. Their primary defense is smearing venom rather than stinging, but given their tiny size, this is negligible to humans. They will likely flee rather than fight. Escape prevention must be excellent, they can squeeze through standard mesh barriers.
• Common Issues: no captive husbandry information exists, this is one of the rarest ant species in the world, tiny size makes escape likely without fine mesh barriers, polygynous structure means multiple queens may need to be kept together, extremely limited distribution makes wild collection unethical and likely illegal, no established feeding protocols exist for this species

Discovery and Rarity

Rotastruma epispina is one of the rarest ant species in the world, known from only a single colony ever documented. It was formally described in 2021 by Hosoishi and Yamane, making it one of the most recently discovered ant species. The entire known range consists of one location in Kampong Thom Province, Cambodia. This extreme rarity means almost nothing is known about their captive care requirements. If you somehow obtain a colony, you would be pioneering their husbandry entirely. The species name 'epispina' refers to their distinctive upward-pointing propodeal spines ^[1].

Identification and Morphology

Workers are tiny at 3.25-3.40 mm total length, with a rectangular head that is longer than wide. Their most distinctive feature is the propodeal spine that curves upward, visible in side profile. The petiole (the segment between the mesosoma and gaster) has a long stalk that is longer than it is high, this is a key identification feature. They have 12-segmented antennae with a 3-segmented club. The body is yellowish-brown with a broad brown band across the first gastral tergite (abdomen). Queens are slightly larger at 3.88-4.01 mm total length ^[1].

Natural History

The only known colony was collected from a dead twig on lower vegetation in a regrowth forest in Cambodia. The presence of two dealate queens in the same nest suggests this species is polygynous (lives with multiple queens). Nothing is known about their diet, foraging behavior, nuptial flight timing, or development in the wild. As a tropical species from Cambodia, they likely experience warm temperatures year-round with seasonal rainfall patterns ^[1].

Housing Recommendations

Since no captive husbandry exists, recommendations must be inferred. Given their natural nesting in dead twigs ^[1], a small test tube setup or Y-tong nest with appropriately scaled chambers would be most suitable. The tiny worker size (3.3 mm) means chambers should be small and tight-fitting. Use fine mesh for escape prevention, standard ant mesh may not retain them. Maintain warm temperatures around 24-28°C and moderate humidity. Provide a moisture gradient so ants can self-regulate. Feed small live prey appropriate to their size, and offer sugar water or honey occasionally. This species should be considered expert-level due to the complete lack of husbandry information.

Legal and Ethical Considerations

This species is known only from a single location in Cambodia ^[1] and is extremely rare in the wild. It should not be collected from the wild. No established breeding populations exist in the antkeeping hobby. If a colony were to become available, it would likely be from a specialized researcher or breeding program. Export from Cambodia may be restricted under CITES or local wildlife laws. Do not release this species or any related ants outside their natural range.

Frequently Asked Questions

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References