Crematogaster monocula

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Known only from lowland forest in Koh Kong, Cambodia at 141m altitude. This is a tropical, subterranean species collected from leaf litter in a warm, humid forest environment ^[1][2].
• Colony Type: Colony structure is unconfirmed. Based on typical Crematogaster patterns, they may form polygynous colonies, but this has not been documented for this specific species.
• Size & Growth:
  • Queen: Size data unavailable, no queen has been described yet ^[1]
  • Worker: ~2-2.5mm, inferred from Crematogaster genus (small species based on head measurements) ^[1]
  • Colony: Unknown, only two workers have ever been collected ^[1]
  • Growth: Unknown
  • Development: Unconfirmed, no breeding data exists for this species (Development timeline is unstudied for this species)
• Antkeeping:
  • Temperature: Keep at 24-28°C, this is a tropical lowland species from Cambodia. A gentle heat gradient allows workers to self-regulate.
  • Humidity: High humidity is essential, they come from damp lowland forest leaf litter. Keep the nest substrate consistently moist but not waterlogged. Mist occasionally and provide a water tube.
  • Diapause: Unlikely, being a tropical Cambodian species, they probably do not require a diapause period.
  • Nesting: This is a subterranean species. Use a setup that allows them to burrow and maintain humidity, a Y-tong (AAC) nest with moist substrate or a naturalistic setup with soil works well. They will likely nest in hidden, dark spaces.
• Behavior: Crematogaster ants are known for their distinctive defensive behavior, they raise their heart-shaped gaster over their head and may bite or sting when threatened. This species is very small so escape prevention is critical, they can squeeze through tiny gaps. They are likely nocturnal or cryptic foragers based on their reduced eyes. Expect them to be shy and reclusive.
• Common Issues: This species is virtually unknown in captivity, no established husbandry protocols exist, Their extremely small size means escape prevention must be excellent, use fine mesh barriers, Only two specimens have ever been collected, so all care recommendations are estimates based on genus patterns, Subterranean species require careful humidity management to prevent desiccation, No confirmed food preferences, start with sugar water and small live prey like springtails

Discovery and Rarity

Crematogaster monocula was only described in 2019 by Shingo Hosoishi, making it one of the newest ant species to science. Only two worker specimens have ever been collected, both from the same location in Koh Kong, Cambodia. The most remarkable feature is their single ommatidium (eye facet), the smallest eye known in the entire genus Crematogaster. This extreme eye reduction suggests they live almost entirely underground or in dark microhabitats, relying less on vision than their relatives ^[1]. The species name literally means 'one eye' in Latin, referring to this unique trait ^[1].

Identification and Morphology

This is a tiny yellow ant, workers have an 11-segmented antenna with a 2-segmented club, and their scape (the first antenna segment) is relatively short (scape index 64-66). The most distinctive feature is the single ommatidium in each eye, compare this to their close relative Crematogaster masukoi which has 5-6 ommatidia. They have developed subpetiolar and subpostpetiolar processes (small projections under the waist segments), which is characteristic of the C. biroi species group within the Orthocrema subgenus ^[1]. Their body is entirely yellow, including all flagellar segments.

Housing and Nesting

Since this is a subterranean species from a tropical lowland forest, they need high humidity and dark nesting conditions. A Y-tong (AAC) formicarium with moist substrate works well, or you could use a naturalistic setup with soil. The key is maintaining consistent moisture without flooding. Because they are so tiny, escape prevention is critical, use tight-fitting lids and consider fine mesh on any ventilation. They will likely prefer to nest in hidden, covered areas rather than exposed chambers. Start with a test tube setup with a water reservoir for founding colonies, transitioning to a more elaborate setup as the colony grows.

Feeding and Diet

While specific feeding data does not exist for this species, Crematogaster generally are omnivores that accept sugar sources (honey water, sugar water) and protein (small insects). Because they are so small, their prey items must be tiny, springtails, fruit flies, and other micro-arthropods are appropriate. Start by offering a sugar water source and small live prey. Remove uneaten prey within 24-48 hours to prevent mold issues. Their tiny size means even small prey items may be challenging, consider cutting larger insects into smaller pieces.

Temperature and Humidity

Being from tropical Cambodia (Koh Kong province), this species needs warm, humid conditions. Aim for temperatures in the 24-28°C range, this matches their natural lowland forest habitat. A slight temperature gradient allows the ants to self-regulate. Humidity should be high, think damp forest floor. The nest substrate should feel consistently moist but never waterlogged. You can achieve this with a water tube attached to the nest or by occasionally misting the setup. Avoid both drying out and creating stagnant, overly wet conditions.

Behavior and Temperament

Crematogaster ants are known for their distinctive defensive behavior, when threatened, they raise their heart-shaped gaster over their head (a behavior called gastral elevation) and may attempt to bite or sting. This species is likely quite shy and reclusive given their subterranean lifestyle and reduced eyes. They probably forage at night or in dark periods rather than during bright daylight. Their tiny size means they are not dangerous to humans, the sting is likely too small to penetrate skin effectively. However, they should still be handled with care and escape prevention is essential due to their ability to squeeze through tiny gaps.

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