Scientific illustration of Odontomachus ruginodis (Rough-node Trap-jaw Ant) - showing key identification features including head, thorax, and gaster.

Rough-node Trap-jaw Ant

Odontomachus ruginodis

Monogynous Non-Parasitic Queen No Gamergate
Sci. Name
Odontomachus ruginodis
Tribe
Ponerini
Subfamily
Ponerinae
Author
Wheeler, 1908
Common Name
Rough-node Trap-jaw Ant
Distribution
Found in 15 countries
Queen Activity
From January to December
Peak Time
18:00
AI Identifiable
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Introduction

Odontomachus ruginodis is a small trap-jaw ant with mandibles that snap shut at speeds up to 50 m/s . Workers are 3.5-4.0 mm long with a reddish-brown body and dark black abdomen . This species is found in the Caribbean, Florida, and northern South America, nesting in soil and under stones in disturbed and natural habitats . It exhibits 'bouncer' defensive behavior, where workers guard the nest entrance with cocked mandibles, snapping at intruders .

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Status by country, from Kass et al. 2022 & Wong et al. 2023

Native Invasive Introduced (indoor) Intercepted Unknown
2000 - 2026

Quick Summary

  • Difficulty: Expert
  • Origin & Habitat: Native to the Caribbean and northern South America, with introduced populations in Florida and the Galápagos Islands. Found in disturbed areas including urban habitats, beaches, open woods, and mangrove areas [3][4]. In Puerto Rico, prefers open sunny areas like river bottoms [3].
  • Colony Type: Monogyne (single queen colonies). Workers are monomorphic (all the same size) [5]. Queens are similar to workers but larger with ocelli and larger compound eyes [2].
  • Size & Growth:
    • Queen: ~4.0-4.5 mm [2]
    • Worker: ~3.5-4.0 mm [2]
    • Colony: Up to about 50 workers in mature colonies, wild colonies are typically small, often around a dozen workers [3][6]
    • Growth: Moderate
    • Development: Estimated 6-10 weeks at optimal temperatures (25-28°C), based on related Odontomachus species [3] (Development time is inferred, colonies remain small compared to many ant species.)
  • Antkeeping:
    • Temperature: Keep at 24-28°C. This is a tropical species, so warmth is essential for activity and brood development [3].
    • Humidity: Keep the nest substrate consistently moist but not waterlogged. These ants nest in soil and under stones in areas that range from dry to moist [3][4].
    • Diapause: No. This is a tropical species that does not require winter diapause [3].
    • Nesting: Ground-nesting species that does well in test tube setups or Y-tong nests with a soil chamber. Provide moist substrate for them to dig in or around [3][4].
  • Behavior: This species is defensive and will aggressively guard its nest. Workers act as 'bouncers' at nest entrances, standing with mandibles cocked and snapping at intruders within striking distance [3][7]. Their trap-jaw mandibles can fling attackers away 1-14 centimeters, and if they hit a solid object, the worker may be flung into the air [3]. They are primarily nocturnal and predatory, hunting small insects [6]. Escape prevention is important due to their active nature.
  • Common Issues: small colony size means slow population growth, do not expect rapid expansion, their trap-jaw defense can fling workers several centimeters, potentially out of poorly secured setups, predatory diet means they need live prey, sugar water alone will not sustain them, colonies often fail if kept too cool, maintain warm temperatures year-round, wild-caught colonies may have parasites that kill them in captivity
Queen Ant Activity Analysis 150 observations
9
Jan
Feb
Mar
19
Apr
May
15
Jun
21
Jul
8
Aug
14
Sep
17
Oct
15
Nov
15
Dec

Odontomachus ruginodis exhibits a clear seasonal activity window. Peak activity is concentrated in July, with the overall period spanning January to December. This extended season suggests multiple flight events or varying conditions across its range.

Queen Activity by Hour 150 observations
00:00
4
01:00
02:00
03:00
04:00
05:00
06:00
07:00
7
08:00
9
09:00
6
10:00
8
11:00
4
12:00
4
13:00
8
14:00
15:00
5
16:00
14
17:00
19
18:00
14
19:00
12
20:00
11
21:00
5
22:00
7
23:00

Odontomachus ruginodis queen activity peaks around 18:00 during the evening. Activity is spread across a 23-hour window (01:00–23:00). Times may be influenced by human observation patterns.

Housing and Nest Setup

Odontomachus ruginodis is a ground-nesting ant that does well in test tube setups or Y-tong formicariums with a soil chamber. Since they naturally nest under stones and in soil, provide a moist substrate like a sand-soil mix for them to dig in or around [3][4]. For established colonies, a Y-tong nest with a dirt chamber or a naturalistic setup with soil and flat stones works well. These ants are nocturnal and somewhat shy, so provide covered areas for security. Use fluon on container rims to prevent escapes, as these active ants can climb smooth surfaces [6].

Feeding and Diet

As predatory trap-jaw ants, they need a protein-rich diet of live prey. Offer small live insects like fruit flies, pinhead crickets, and small worms [3][6]. They may occasionally accept dead prey, but hunting behavior is natural enrichment. Feed them prey 2-3 times per week, adjusting for colony size. Remove uneaten prey after 24 hours to prevent mold. Sugar water or honey can be offered occasionally, but protein is essential for survival and brood production [8].

Temperature and Seasonal Care

Keep your colony at 24-28°C (75-82°F). This tropical species needs warmth for activity and brood development [3]. A heating cable on one side of the nest creates a gradient. Room temperature in the low-to-mid 70s°F is usually adequate. They do not require diapause, but activity may slow if temperatures drop [3]. They are primarily nocturnal, so they will be most active during evening and night hours.

Behavior and Defense

This species is famous for its 'bouncer' defense. Workers stand guard at the nest entrance with mandibles cocked, snapping at intruders within striking distance [3][7]. Their mandibles can strike at speeds up to 50 m/s, flinging attackers away 1-14 centimeters [1][9]. If mandibles hit a solid object, the worker may be flung into the air but immediately returns to fight [3]. Their sting is reported to be painful among Caribbean ants [8]. Handle nests with care due to this defensive behavior.

Colony Development

Colonies start with a single queen who raises the first brood alone. The first workers (nanitics) will be smaller than mature workers. Growth is slow, wild colonies are typically around a dozen workers [3][6]. Mature colonies may reach up to 50 workers but rarely become massive. Males are produced in larger colonies and have been collected from early May through June in Florida [3]. Adjust expectations for small colony size.

Frequently Asked Questions

How long does it take for Odontomachus ruginodis to produce first workers?

Expect 6-10 weeks from egg to first worker at optimal temperatures (25-28°C), based on related Odontomachus species [3]. Specific development timing for this species is not documented.

Can I keep multiple queens together?

No. This is a monogyne species with a single queen per colony [5]. Combining unrelated queens will likely result in fighting.

Do these ants sting?

Yes, and it is reported to be one of the more painful stings among Caribbean ants [8]. However, their primary defense is their trap-jaw snap.

What do I feed Odontomachus ruginodis?

They need live prey like fruit flies, pinhead crickets, and small worms [3][6]. Feed them 2-3 times per week, protein is essential for survival.

Are Odontomachus ruginodis good for beginners?

No, they are rated as Expert difficulty due to invasive status and care requirements [3][4]. They need warm temperatures, live prey, and have slow-growing colonies.

How big do colonies get?

Colonies remain small, in the wild, they typically have around a dozen workers [3][6]. In captivity, they may reach up to 50 workers but rarely become massive.

Do they need hibernation?

No. This is a tropical species that does not require diapause [3]. Keep them warm year-round.

When should I move them to a formicarium?

Keep them in a test tube setup during founding. Once the colony has 20-30 workers and consistent brood, move to a Y-tong or naturalistic setup with a soil chamber [3][4].

Why is my colony dying?

Common causes include: too cool temperatures (keep at 24-28°C), lack of live prey, too dry conditions, or parasites from wild-caught colonies [3]. Check temperature and diet first.

When do Odontomachus ruginodis queens forage?

Queen activity of Odontomachus ruginodis typically occurs From January to December. Times may be influenced by human observation patterns.

What time of day are Odontomachus ruginodis queens most active?

Queen activity of Odontomachus ruginodis peaks around 18:00 during the evening, with most activity between 01:00 and 23:00. Times may be influenced by human observation patterns.

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References

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This caresheet is licensed under CC BY-SA 4.0 .