Lordomyrma tortuosa

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Fiji endemic, recorded from 8 islands. Lives in lower elevations, mostly below 500 m. Nests in small colonies under logs, stones, and in leaf litter ^[1][2]. Forages on mossy stones and riverbank surfaces ^[1].
• Colony Type: Unconfirmed – likely single-queen based on typical Myrmicinae patterns. Nests found to be small ^[2].
• Size & Growth:
  • Queen: Not documented in primary literature
  • Worker: 4.15–4.53 mm ^[1]
  • Colony: Small colonies – exact maximum unknown, but nests in logs and under stones suggest modest size ^[2]
  • Growth: Moderate – inferred from typical Myrmicinae development
  • Development: Unknown – no direct data. Based on typical Myrmicinae in tropical conditions, possibly 6–8 weeks at 26°C, but this is an estimate (Tropical species likely develops faster than temperate relatives, no specific data available.)
• Antkeeping:
  • Temperature: Keep at 24–28°C – tropical Fiji species requires warmth. Provide a gentle gradient for self-regulation
  • Humidity: High humidity – keep nest substrate consistently moist but not waterlogged. These ants come from damp forest floor and mossy environments ^[1][2]
  • Diapause: No – tropical species, no hibernation needed. Keep warm year-round
  • Nesting: Prefers naturalistic setups with moist substrate. Use Y-tong (AAC) or plaster nests – avoid acrylic. Provide damp soil/sand mix. Small colony size means compact nest chambers ^[1][2]
• Behavior: Workers actively forage on surfaces, gleaning small prey from stones ^[1]. They have a sting but it's weak – described with reduced sides and a weak apex ^[3]. Escape risk is moderate due to medium worker size. Generally not aggressive but will sting if provoked. Forages above ground rather than only in soil.
• Common Issues: small colony size makes colonies fragile and sensitive to disturbance, high humidity needs can cause mold if ventilation is poor, weak sting may lead to underestimating their defensive capability, lowland origin means they don't tolerate cool temperatures, population status unknown – avoid collecting in Fiji where endemic

Natural History and Distribution

Lordomyrma tortuosa is endemic to Fiji, making it a special species for keepers interested in Pacific ants. It's the most widespread Lordomyrma on the archipelago, confirmed from eight islands: Beqa, Gau, Kadavu, Koro, Moala, Taveuni, Vanua Levu, and Viti Levu ^[1][2]. This broad distribution suggests it can adapt to different local conditions.

The species strongly prefers lower elevations – only 2 out of 32 records are above 500 m altitude ^[1]. That means they like warmer, likely more humid conditions than highland species. In the wild, workers forage on mossy stones in ravines and glean surfaces along river banks ^[1]. This gleaning behavior – picking small prey from surfaces – is different from typical ground foraging.

Nests are found in decaying logs and under stones, showing a preference for moist, sheltered spots ^[2]. Colonies are small, as expected from those nest types ^[2]. Originally described as Rogeria (Irogeria) tortuosa by Mann in 1921,it was later moved to Lordomyrma by Kugler in 1994 ^[4][5].

Identification and Morphology

Lordomyrma tortuosa is a relatively large Myrmicinae, with workers 4.15–4.53 mm long ^[1]. The most striking feature is the massive promesonotum (fused thorax) – strongly convex and bulging above both head and propodeum when seen from the side ^[1][2]. This gives it a hunched, arched look.

The head and body are shiny reddish-brown, with lighter legs and antennae ^[1]. The face has strong curved ridges (arcuate carinae) that run from near the eyes toward the back of the head, forming the upper edge of a broad, shallow groove for the antenna ^[1]. There are also longitudinal ridges inward from the frontal carinae, another key ID feature ^[2].

Propodeal spines are modest, straight, and triangular – about as wide as the front leg base ^[1]. All upper surfaces have lots of suberect to erect hairs, the longest equal to or longer than the eye ^[1]. This hairy look is typical of the genus. Together with Lordomyrma desupra, Lordomyrma stoneri, and Lordomyrma vuda, it lacks a transverse carina on the propodeum and has a bulging promesonotum ^[2].

Housing and Nest Preferences

For captive care, set up a naturalistic or semi-naturalistic enclosure that mimics their log-and-leaf-litter habitat. Use a Y-tong (AAC) or plaster nest with a chamber volume of about 10–20 ml for starting colonies. Scale up as the colony grows. Plaster nests with built-in water chambers help maintain humidity.

The key is consistently high humidity. These ants come from damp forest floor and mossy river banks ^[1], so keep the nest substrate moist but not waterlogged. A moisture gradient works well – let one section be slightly damper while another is moderately moist.

Because colonies stay small (likely under a few hundred workers), avoid oversized nests. Tight-fitting lids are essential – they're not tiny but can still squeeze through small gaps. Use standard escape prevention for medium Myrmicinae.

Decorate the outworld with leaf litter, moss, and small stones to encourage natural foraging. Since workers glean surfaces in the wild ^[1], textured surfaces in the foraging area may boost activity.

Feeding and Diet

In the wild, Lordomyrma tortuosa workers actively forage on surfaces and pick off small prey from stones ^[1]. That makes them generalist predators, likely eating springtails, mites, and other small litter invertebrates.

For captive feeding, offer small live prey like fruit flies, pinhead crickets, small mealworms, and especially live springtails. Springtails are an ideal staple – they match natural prey size and can live in the outworld. Also offer other small insects.

Sugar sources may be accepted, though this species isn't primarily a honeydew feeder. You can try a drop of diluted honey or sugar water occasionally, but protein should be the main food. Watch your colony's preferences.

Feed small prey 2–3 times a week for established colonies. Remove uneaten prey after 24–48 hours to prevent mold in the humid setup.

Temperature and Seasonal Care

As a tropical Fiji endemic, Lordomyrma tortuosa needs warm conditions all year. Keep the nest area at 24–28°C. Use a heating cable or mat on one side to create a gentle thermal gradient, so workers can choose their spot.

Unlike temperate ants, this species doesn't need hibernation (diapause). Maintain consistent warmth for good colony health. Avoid letting the temperature drop below 20°C for long periods, since they're adapted to lowland tropical conditions.

The lowland preference (most records below 500 m) means they like it warm – room temperature alone may not be enough in cooler climates. Supplemental heating is recommended. ^[1]

Defense and Sting

Lordomyrma tortuosa has a functional stinger, shown in Kugler's 1997 study of sting morphology in the genus ^[3]. However, the sting is described as weak, with reduced sides and a weak apex ^[3]. So it's not as potent as some other Myrmicinae.

In practice, these ants are not aggressive and usually flee when disturbed. They may sting if cornered or if the nest is threatened, but the sting is mild – noticeable but not severe.

For keepers, standard precautions are enough. The sting isn't dangerous, but avoid provoking the colony, especially the queen during founding.

Frequently Asked Questions

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References