Lordomyrma rugosa

Lordomyrma rugosa

Lordomyrma rugosa is a medium-sized ant endemic to the Fiji Islands, specifically found only in the Nadarivatu and Mount Tomaniivi area on Viti Levu ^[1][2]. Workers measure 3.36-3.77mm and are dark reddish brown with a distinctive heavily sculptured appearance, the face and mesosoma are covered in a thick rugoreticulum (wrinkled texture), and they possess long upturned propodeal spines ^[1][3]. This species is unique among all Fijian Lordomyrma for bearing strong striations on both its mandibles and procoxae (front legs) ^[1][2]. Colonies are small, with documented nests containing around 66 workers, and they live beneath stones or directly in soil with a tiny 1mm entrance hole ^[1][3]. Workers move slowly, making them a calm and observable species in captivity.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Endemic to Fiji, found only in the Nadarivatu and Mt. Tomaniivi area on Viti Levu island. They live in small colonies beneath stones or directly in clay soil, typically in bare ground areas with tiny 1mm nest entrances ^[1][2][3].
• Colony Type: Small colonies with single queen likely, colonies documented at around 66 workers suggest moderate colony size. Colony structure is not extensively studied but small colony size suggests monogyne (single queen) colonies ^[1][3].
• Size & Growth:
  • Queen: Unconfirmed, no specific measurements documented in available literature ^[1].
  • Worker: 3.36-3.77mm ^[1][3].
  • Colony: Small, up to approximately 66 workers documented in wild colonies ^[1][3].
  • Growth: Unknown, likely moderate based on small colony sizes observed.
  • Development: Unconfirmed, no development studies exist for this species. Based on typical Myrmicinae patterns from similar tropical ants, estimate 6-10 weeks at optimal temperature. (Development timeline has not been directly studied. Estimates based on genus-level patterns for related Crematogastrini.)
• Antkeeping:
  • Temperature: Keep at 22-26°C, as a tropical Fiji species, they prefer warm conditions. A gentle gradient allowing workers to choose their preferred temperature is ideal.
  • Humidity: High humidity preferred, they nest in clay soil in a humid tropical environment. Keep the nest substrate consistently moist but not waterlogged, with some drier areas available for the ants to self-regulate.
  • Diapause: Unlikely, as a tropical species from Fiji, they probably do not require a true diapause. However, a slight reduction in temperature during winter months may be beneficial to simulate natural seasonal cycles.
  • Nesting: Soil-nesting species, in captivity they do well in test tubes with soil or a plaster nest with moisture. The natural nesting sites are in clay soil beneath stones or directly in ground with small entrances. A naturalistic setup with a soil chamber works well ^[1][3].
• Behavior: Workers are slow-moving and calm, making them an excellent species for observation. They are not aggressive and likely forage individually for small prey and honeydew. Their small size (under 4mm) means escape prevention should be considered, they can squeeze through small gaps. The slow movement makes them less likely to climb aggressively, but fine mesh barriers are still recommended ^[1][3].
• Common Issues: small colony size means colonies develop slowly and may be vulnerable to stress, slow growth can lead to impatient keepers overfeeding or disturbing the nest, escape prevention is important despite slow movement, their tiny 1mm natural entrance size shows they can fit through very small gaps, limited availability as an endemic Fiji species, may be difficult to acquire, humidity control is critical, drying out can stress or kill colonies faster than in more resilient species

Natural History and Distribution

Lordomyrma rugosa is one of the most distinctive species of Lordomyrma in Fiji, known for its heavy rugoreticulum (wrinkled sculpture) covering the face and mesosoma ^[2]. This species is endemic to Fiji and known only from the Nadarivatu and Mt. Tomaniivi area on Viti Levu island, a very restricted range ^[1][2][4]. The original description was published by Mann in 1921 under the name Lordomyrma rugosa, and it was later transferred to the genus Lordomyrma by Kugler in 1994 ^[5]. What makes this species particularly unique is that it is the only known Fijian Lordomyrma to bear strong striations on both its mandibles and procoxae ^[1][2]. Colonies are small, living beneath stones or directly in the ground, with workers moving slowly as they go about their daily activities ^[1][3].

Housing and Nest Preferences

In the wild, Lordomyrma rugosa nests in clay soil beneath stones or directly in the ground, with tiny 1mm entrance holes flush with the soil surface ^[1][3][2]. For captivity, a naturalistic setup with a soil chamber works best, this allows you to replicate their natural underground environment. Test tubes with a soil chamber or plaster nests with moisture retention are both suitable options. The key is maintaining consistently moist substrate without waterlogging. Because they naturally nest under stones in humid conditions, the nest should not be allowed to dry out. A small water reservoir connected to the nest area helps maintain humidity. These ants are not aggressive climbers, so standard escape prevention measures suffice, though their small size means fine mesh is still recommended ^[1][3].

Feeding and Diet

While specific dietary studies do not exist for L. rugosa, Lordomyrma species are generally omnivorous like most Myrmicinae, feeding on small insects, honeydew, and nectar. In captivity, offer a varied diet including small live prey (fruit flies, pinhead crickets, mealworms) and sugar sources (honey water, sugar water). Their slow-moving foragers mean they will likely take longer to discover food, place offerings near the nest entrance and be patient. Protein-rich foods are important for brood development. Given their small colony sizes, feed small amounts frequently rather than large prey items that may go uneaten. Remove uneaten prey after 24-48 hours to prevent mold.

Temperature and Seasonal Care

As a tropical species endemic to Fiji, Lordomyrma rugosa prefers warm conditions. Keep the nest area at 22-26°C, with a gentle gradient allowing workers to self-regulate. Fiji has a warm, humid tropical climate year-round, so these ants do not require hibernation. However, a slight seasonal variation may be natural, you might reduce temperatures by a few degrees during winter months, but this is not required. Avoid temperatures below 18°C or above 30°C. A heating cable on one side of the nest can create the ideal gradient, but ensure it does not dry out the substrate too quickly. Monitor condensation levels as an indicator of humidity.

Behavior and Observation

One of the most appealing aspects of Lordomyrma rugosa is their calm, slow-moving nature. Workers are described as slow-moving even in the wild, making them excellent for observation in captivity ^[1][2][3]. They are not aggressive and likely forage individually rather than in raiding parties. Their small colony size (typically under 100 workers) means you can observe the entire colony dynamics without it becoming overwhelming. The heavily sculptured appearance and distinctive propodeal spines make them visually interesting. Watch for behaviors like brood care, foraging, and nest maintenance, these slow ants give you time to observe each individual.

Frequently Asked Questions

References