Myrmecia simillima

Myrmecia simillima - "Australian Red Bull Ant"

Myrmecia simillima is a large, aggressive bull-dog ant native to Australia, belonging to the gulosa species group ^[1]. Workers are robust ants with powerful mandibles and a painful sting. They form populous colonies under large stones and Eucalyptus logs ^[2]. This species is notable for having both brachypterous (wingless) and ergatoid (worker-like) queens, which affects how colonies reproduce and expand ^[2]. Unlike many ants that seal themselves away to raise their first workers, these queens must leave the nest to hunt for food during founding, a behavior called semi-claustral colony founding ^[2].

Quick Summary

• Difficulty: Medium to Hard
• Origin & Habitat: Australia, found across multiple states including New South Wales, South Australia, and Victoria. Nests are located under large stones and Eucalyptus logs in forested areas ^[2].
• Colony Type: Single-queen colonies with ergatoid replacement reproductives. Both brachypterous (wingless) and ergatoid queens have been described, allowing for colony reproduction through fission when the colony splits ^[2].
  • Colony: Monogyne
  • Founding: Semi-claustral
• Size & Growth:
  • Queen: Estimated 15-18mm based on genus Myrmecia patterns
  • Worker: Estimated 12-15mm based on genus Myrmecia patterns
  • Colony: Populous colonies, likely several hundred to over 1000 workers based on field observations ^[2]
  • Growth: Moderate, semi-claustral founding is slower than claustral species
  • Development: Estimated 8-12 weeks based on related Myrmecia species at warm temperatures (Semi-claustral founding extends development time as the queen must leave to forage)
• Antkeeping:
  • Temperature: Keep at 24-28°C with a slight gradient. Room temperature is acceptable if within this range.
  • Humidity: Moderate humidity around 50-60%. They nest under stones in nature, so the nest area should be kept slightly moist but not wet.
  • Diapause: No, being Australian, they do not require hibernation. Keep at stable warm temperatures year-round.
  • Nesting: Y-tong (AAC) nests or plaster nests work well. Provide a spacious outworld for foraging. These are large ants that need room to move.
• Behavior: Extremely aggressive and defensive of their nest. Workers will readily attack any threat and have a painful sting, rated 1.5 on the Schmidt pain scale with venom lethality at 0.21 mg/kg LD50 ^[3]. They are active foragers, hunting insects and other prey. Escape prevention is important but not due to their small size, these are large ants that cannot squeeze through standard formicarium barriers. However, their aggressive nature means handling requires caution.
• Common Issues: Semi-claustral founding is challenging, queens must be fed during founding, which many keepers miss, Painful stings mean these ants are not suitable for handling or for households with curious pets or children, Colony fragmentation through fission may catch keepers off guard, ergatoid queens can establish new colonies nearby, Wild-caught colonies may have parasites that cause problems in captivity, Their aggressive temperament makes routine colony maintenance more difficult

Housing and Nest Setup

Myrmecia simillima are large, aggressive ants that need spacious housing. Y-tong (AAC) nests or plaster formicaria work well because they provide good humidity control and allow you to observe the colony. The nest chamber should be sized appropriately for their colony size, these ants form populous colonies, so plan for growth. A large outworld is essential for foraging and hunting. Use a water tower setup for humidity, these ants prefer moderate humidity around 50-60% in the nest area. Escape prevention is straightforward since they are large ants, but the aggressive nature means you should still use secure barriers and keep lids tight when working with the colony. ^[2]

Feeding and Diet

Myrmecia simillima are specialist predators, in the wild they hunt insects like saw-fly larvae and other small invertebrates ^[2]. In captivity, offer live insects such as mealworms, crickets, and other appropriately-sized prey. They will readily accept protein foods and should be fed several times per week depending on colony size. Sugar sources like honey water or sugar water can be offered occasionally, but protein is the primary food needed for growth. For founding colonies, the queen must be fed directly, this is critical for semi-claustral species. Drop small prey items near the queen so she can hunt and feed.

Temperature and Seasonal Care

Keep Myrmecia simillima warm at 24-28°C. As an Australian species, they do not require hibernation or diapause, maintain stable temperatures year-round. A heating cable on one side of the nest can create a gradient, allowing ants to choose their preferred temperature. Avoid temperatures below 20°C for extended periods. Room temperature is often suitable if your home stays in the low-to-mid 20s Celsius. Monitor colony activity, if workers become sluggish, increase temperature slightly. ^[2]

Colony Founding and Reproduction

This species has a unique colony founding strategy, semi-claustral. Unlike most ants where the queen seals herself away and lives on stored fat, Myrmecia simillima queens must leave the nest to hunt for food while raising their first workers ^[2]. This makes founding colonies more challenging for keepers. Additionally, both brachypterous (wingless) and ergatoid (worker-like) queens have been documented. Ergatoid queens can serve as replacement reproductives if the primary queen dies, and they can also establish new colonies through fission, where the colony splits and a new queen leaves with workers to form a separate colony ^[2]. This means established colonies may produce ergatoid queens that could potentially establish nearby.

Handling and Safety

Myrmecia simillima has a painful sting rated 1.5 on the Schmidt scale, with venom lethality at 0.21 mg/kg ^[3]. These ants are exceedingly ferocious and will attack aggressively when their nest is disturbed ^[2]. For these reasons, they are not recommended for keepers who want to handle their ants or for households with children or pets that might provoke the colony. When working with the colony, use caution, avoid sudden movements, use gentle lighting, and consider using smoke or air flow to calm them before opening the nest. Always wear protective clothing if you need to open the nest for maintenance.

Frequently Asked Questions

References