Vollenhovia okinawana

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Okinawa Island, Japan, found in decaying wood in forests ^[2][1].
• Colony Type: Colony structure varies by population. The widespread form likely has a single winged queen, a separate population in northern Okinawa uses ergatoid (wingless) females as reproductives ^[1].
• Size & Growth:
  • Queen: ~2.6 mm total length ^[1]
  • Worker: 2.0-2.5 mm total length ^[1][2]
  • Colony: Unknown, no published data. Similar Vollenhovia species probably have small colonies, likely under a few hundred workers.
  • Growth: Slow to moderate (estimated from related species)
  • Development: No specific data, development likely takes several weeks at warm temperatures, similar to other small Myrmicinae. (Timing is inferred from related species, exact data not available.)
• Antkeeping:
  • Temperature: Subtropical origin suggests warm conditions. Keep at 22-26 °C, but precise requirements are undocumented. Provide stable warmth and avoid extremes ^[2][1].
  • Humidity: High, they nest in decaying wood in forests ^[2][1]. Keep nest substrate damp but not waterlogged.
  • Diapause: Not required due to subtropical origin ^[2], but if kept in cool climates, a short winter cooling (e.g.,10-15 °C for a few weeks) may be safe, though unconfirmed.
  • Nesting: Provide decaying wood or a test tube with moist substrate. Use narrow chambers (3-5 mm) to prevent escapes. Y‑tong or plaster nests work well, but avoid tall open spaces ^[2][1].
• Behavior: Vollenhovia okinawana is docile and not aggressive. Like other members of the tribe Crematogastrini, its main defense is smearing venom onto enemies using a modified stinger. However, they rarely use it in captivity. Their tiny size (under 3 mm) makes escape prevention critical, even the smallest gaps in tubing or lid seals will allow them out. Use fine mesh (0.5 mm) and seal all connections.
• Common Issues: tiny size makes escape easy, use 0.5 mm mesh and tight seals., specific humidity needs, too dry stops brood, too wet causes mold., growth is slow, colonies take many months to build up., workers can get stuck in water feeders, provide shallow sources or cotton‑plugged tubes., wild‑caught nests may carry parasites, quarantine new colonies.

Housing and Nest Setup

Because workers are only about 2 mm long, you need a nest with small chambers. A test tube with a water reservoir and tightly packed cotton works well for starting a colony ^[2][1]. For a larger colony, use a Y‑tong (AAC) or plaster nest with narrow passages (3-5 mm wide and high) so workers don't get lost in big open spaces. These ants naturally live in decaying wood in forests ^[2][1], so adding a piece of soft wood or cork can make them feel at home. Avoid tall chambers and always seal every gap, even the smallest opening will let them escape.

Feeding and Diet

In the wild, Vollenhovia okinawana likely scavenges small insects and drinks honeydew. In captivity, offer tiny protein sources such as fruit flies, pinhead crickets, or chopped mealworms. Sugar water or diluted honey gives them energy. Feed small amounts two to three times a week and remove uneaten prey after 24 hours to stop mould. Because workers are so tiny, cut prey into pieces no larger than their head, anything bigger will be ignored. A constant supply of sugar water helps small colonies grow ^[2].

Temperature and Seasonal Care

Vollenhovia okinawana comes from subtropical Okinawa, so it likes warmth. Keep the nest at 22-26 °C for good brood development. Create a slight temperature gradient so workers can choose their own spot. They do not need hibernation, Okinawa has mild winters, so they stay active all year if kept warm ^[2]. If your room gets below 20 °C in winter, use a heating cable on one side of the nest. Avoid long periods above 30 °C or below 18 °C.

Colony Structure and Reproduction

This species has two known reproductive strategies. In most of Okinawa, the ants produce normal winged queens (alates) that fly out to mate and start new colonies. In the northern part of the island, a separate population makes only ergatoid (wingless) females that stay in the nest as reproductives ^[1]. The workers and males of both groups look exactly the same ^[1]. If you collect a queen, she will probably be of the winged type. No studies have confirmed how she founds a colony, but it is probably claustral (sealing herself in a chamber and rearing the first workers on her body reserves), as is common in Myrmicinae. Be patient, small colonies grow slowly.

Handling and Temperament

These ants are very docile and rarely show aggression. They do not sting or bite noticeably. When you open the nest, they may run around quickly but will not try to attack you. Because they are so small, handle them gently, they can easily be crushed. Keep them away from larger ant species, which might prey on them. The biggest challenge is preventing escapes, not dealing with defensive behaviour. Use fine mesh and seal all joints ^[1].

Frequently Asked Questions

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References