Crematogaster fumikoae

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Northern Thailand and Northern Vietnam in the Indomalaya region. Type locality is Doi Suthep near Chiang Mai, Thailand, with additional specimens from Tam Dao, Vietnam at about 1000m elevation ^[1]. Forested mountain environments.
• Colony Type: Unconfirmed, colony structure has not been documented in scientific literature.
• Size & Growth:
  • Queen: Size data unavailable, queen has not been described in the scientific literature ^[1]
  • Worker: ~2-4mm, inferred from typical Crematogaster genus size range
  • Colony: Unknown, no colony size data available
  • Growth: Unknown
  • Development: Unknown, no species-specific development data exists (Development timeline must be learned through observation in captivity.)
• Antkeeping:
  • Temperature: Temperature requirements are unconfirmed, based on tropical/subtropical origin, room temperature (20-26°C) is likely suitable. The mountain localities suggest they may tolerate slightly cooler conditions.
  • Humidity: Likely prefers moderate to high humidity based on forested collection sites. Keep the nest substrate consistently moist but not waterlogged. Provide a humidity gradient so ants can choose their preferred level.
  • Diapause: Unknown, no research on seasonal dormancy. The mountain habitats in Thailand and Vietnam experience cooler dry seasons, so they may have some form of winter slowdown, but this is unconfirmed.
  • Nesting: Likely prefers nesting in rotting wood, under bark, or in small cavities in dead twigs, typical for Crematogaster species. In captivity, a small Y-tong nest or plaster nest with appropriately scaled chambers would work. Their tiny size means chambers must be small.
• Behavior: Behavior is unstudied in captivity. The genus Crematogaster is known for their defensive behavior, they can curl their gaster upward to spray formic acid or sticky secretions at threats. They are generally more aggressive when their nest is disturbed. Workers are small and may be able to escape through standard mesh barriers. Foraging style is unknown but likely involves recruiting to food sources and tending aphids for honeydew.
• Common Issues: no captive biological data exists, all care recommendations are inferred from genus patterns, tiny worker size may require fine mesh barriers to prevent escapes, growth rate is unknown so beginners may struggle to assess colony health, humidity requirements are unconfirmed and must be learned through observation, no information on founding behavior, queen founding type is unconfirmed

Discovery and Naming

Crematogaster fumikoae was described in 2015 by Hosoishi and Ogata, making it one of the more recently discovered ant species available in the antkeeping hobby. The species was found in northern Thailand near Chiang Mai and in northern Vietnam. It was named in honor of Ms. Fumiko Yamane, who collected the type material ^[1]. The species belongs to the Crematogaster popohana group, which includes a handful of similar species found across Southeast Asia. This group is distinguished from other Asian Crematogaster by their slender petiole with weakly convex sides ^[1]. The fact that this species was only recently identified shows how much we still have to learn about ant diversity in Southeast Asia.

Identification and Appearance

Workers of Crematogaster fumikoae show weak polymorphism, meaning some workers are slightly larger than others, but the size difference is not dramatic ^[1]. The body is reddish-brown except for the gaster (the final abdominal segment), which is dark brown, giving them a two-toned appearance. Their most distinctive features include propodeal spines (the spines on the back of the thorax) that curve upward at their tips, and a densely sculptured mesopleuron (the side of the middle body segment). The petiole (the narrow waist segment) is slender and elliptical ^[1]. These are subtle anatomical features that matter more for scientific identification than for everyday antkeeping.

Natural Habitat and Distribution

This species is known from just two countries: Thailand and Vietnam, specifically the northern regions. The type locality is Doi Suthep, a mountain near Chiang Mai in northern Thailand. Additional specimens were collected from Tam Dao in northern Vietnam at about 1000m elevation ^[1]. This suggests they prefer forested mountain environments rather than lowland areas. The Indomalaya region where they live experiences tropical and subtropical climates with distinct wet and dry seasons. The higher elevations provide cooler temperatures than the lowlands. Without field observations, exact microhabitat preferences are unknown, but based on related species, they likely nest in rotting wood, under bark, or in dead twigs on the forest floor.

Defense Mechanism

Crematogaster fumikoae belongs to the subfamily Myrmicinae and tribe Crematogastrini. Members of this tribe have a modified, flattened stinger used to wipe or smear venom onto enemies rather than piercing flesh. This is different from ants that simply sting, they can apply their venom by dragging the stinger across a surface. The spray can be irritating to skin and eyes. When handling these ants, be aware that they may attempt to smear venom if they feel threatened.

Caring for an Undescribed Species

Crematogaster fumikoae presents a unique challenge: there is no published information about keeping this species in captivity. Everything in this caresheet comes from educated guesses based on what we know about the genus and related species. This makes them a species for more experienced antkeepers who are comfortable experimenting and observing their colonies closely. Start with typical Crematogaster care: a small nest with appropriately sized chambers, moderate to high humidity, and room temperature. Watch your colony carefully and adjust conditions based on their behavior. Keep detailed notes about what works and what does not. Your observations could contribute to our understanding of this species. Because they are small, use fine mesh or fluon on any escape routes.

Feeding and Diet

The natural diet of Crematogaster fumikoae has not been studied, but Crematogaster species generally are omnivorous. They likely forage for honeydew from aphids and scale insects, and they will hunt small insects and arthropods. In captivity, offer a varied diet: sugar sources like honey water or sugar water, and protein sources like small insects. Because workers are small, prey items should be appropriately sized. Start with small live prey and observe whether workers can subdue and transport it. Some antkeepers have success with pre-killed prey for very small species. Remove any uneaten prey after 24-48 hours to prevent mold.

Nesting in Captivity

Because this is a small species with no documented nesting preferences, you will need to experiment. Based on typical Crematogaster behavior and the fact that they were found in forested mountain areas, they likely prefer humid nests with access to small cavities. A small Y-tong nest with tight chambers would be a good starting point, as these provide humidity control and allow you to observe the colony. Alternatively, a small plaster nest or a naturalistic setup with rotting wood pieces could work. The key is to scale the nest to their size, chambers should be small and passages narrow. Make sure the nest material can hold moisture without becoming waterlogged. Provide an outworld (foraging area) that is appropriately sized for such small ants.

Frequently Asked Questions

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References