Notostigma carazzii

Notostigma carazzii

Notostigma carazzii is one of the largest ants in Australia and arguably the largest member of the subfamily Formicinae. Workers are a dull deep brown to almost black color, with the head typically darker and shiny, especially in the large-headed soldiers. Soldiers can have head widths exceeding 6mm, with the back of the head deeply concave in the largest individuals. This species is native to Queensland, Australia, where it inhabits rainforests and wet sclerophyll forests. Nests are built in soil at the base of large trees, with large open entrances often sheltered by tree roots or rotting wood. What makes N. carazzii unique is its strictly nocturnal lifestyle, colonies are completely quiescent during the day but become highly active at night, with workers foraging solitarily many meters from the nest and defending the colony aggressively after dark.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Queensland, Australia, found in rainforests and wet sclerophyll forests at elevations between 200-1000m. Nests are constructed in soil at the base of large trees with large, open entrances often sheltered by exposed tree roots or rotting wood.
• Colony Type: Colony structure is unconfirmed, likely monogyne (single queen) based on typical Formicinae patterns, but no specific study has documented queen number.
• Size & Growth:
  • Queen: Undocumented, estimated 15-20mm based on the exceptionally large soldier caste
  • Worker: Workers 8-15mm, soldiers can exceed 6mm head width
  • Colony: Unknown, likely moderate to large based on colony size in related large Formicinae
  • Growth: Moderate, estimated based on typical Formicinae development
  • Development: Estimated 8-12 weeks at optimal temperature based on related Formicinae species (Development time is estimated from genus-level data since no direct species-specific study exists. Expect slower growth than smaller ant species.)
• Antkeeping:
  • Temperature: Keep at 22-26°C. As a tropical Australian species, they prefer warm conditions but avoid overheating. A gentle temperature gradient allows workers to self-regulate.
  • Humidity: Maintain moderate to high humidity (60-80%). These rainforest ants need consistently moist substrate. Mist the outworld regularly and ensure the nest area stays damp but not waterlogged.
  • Diapause: Likely minimal or no true diapause, as a tropical species from Queensland, they probably experience reduced activity in cooler months rather than full hibernation. Reduce feeding and lower temperature slightly (to around 18-20°C) during Australian winter months (June-August) if colony shows reduced activity.
  • Nesting: Provide a spacious formicarium with deep soil chambers (at least 10-15cm deep). In the wild, chambers extend to at least 0.5m underground. Y-tong or naturalistic setups with deep substrate work well. Ensure nest entrances are large and open, as they prefer.
• Behavior: N. carazzii is a nocturnal species with a dramatic shift in behavior between day and night. During the day, the colony is quiescent inside the nest with few defenders present. At night, workers become highly active, foraging, excavating soil, and defending aggressively. They spray formic acid as a defense mechanism, which has a distinctive smell when disturbed. Workers forage solitarily over long distances and navigate visually. They are not aggressive toward keepers during the day but can deliver a painful spray if provoked at night when defenders are active. Escape prevention is important for this medium-to-large species, they can climb smooth surfaces but are not extreme escape artists. Handle with care due to their formic acid spray.
• Common Issues: nocturnal activity pattern may confuse new keepers who expect daytime activity, formic acid spray can be irritating to skin and eyes, avoid disturbing the nest at night, deep nesting requirement means they need spacious formicarium setups, wild-caught colonies may be difficult to establish due to their specific habitat requirements, patchy natural distribution suggests they may have specific microhabitat needs that are hard to replicate

Housing and Nest Setup

Notostigma carazzii requires a spacious setup due to its large size and deep nesting behavior. In the wild, chambers extend at least 0.5m underground, so provide deep substrate of at least 10-15cm in a formicarium. Y-tong nests with large chambers or naturalistic setups with deep soil work well. The nest entrance should be large and open, these ants naturally have large, conspicuous nest openings. Place the nest in a quiet, dark location since they are strictly nocturnal. The outworld should be spacious with multiple foraging areas. Use a water reservoir system to maintain humidity without frequent misting. A layer of gravel and a water tower on the outworld helps maintain moisture.

Feeding and Diet

As a Formicinae species, N. carazzii likely has an omnivorous diet typical of the subfamily. They probably consume honeydew from sap-feeding insects, nectar from flowers, and protein from insects. In captivity, offer sugar water or honey as a constant energy source. For protein, provide insects (crickets, mealworms, roaches) appropriate to their size. They are nocturnal foragers, so place food in the outworld in the evening and remove uneaten portions in the morning. Based on their large size, they can handle prey items significantly larger than what smaller ants accept. The lack of Blochmannia bacteria in this species (unlike most Formicinae) suggests they may have different nutritional requirements, but the exact implications for captive diet are unclear.

Temperature and Seasonal Care

Keep Notostigma carazzii at 22-26°C, mimicking their Queensland rainforest habitat. They prefer warm, stable conditions but should be kept away from direct heat sources that could dry out the nest. A heating cable on one side of the nest can create a temperature gradient, allowing workers to self-regulate. Place the heating on top of the nest, not underneath, to avoid evaporating moisture too quickly. As a tropical species from northern Queensland, they likely do not require true hibernation. During Australian winter (June-August), you may notice reduced activity, this is normal. You can slightly reduce temperature to 18-20°C and reduce feeding frequency during this period, but full diapause is not necessary.

Behavior and Defense

This species has one of the most dramatic behavioral shifts of any ant, they are strictly nocturnal. During daylight hours, the colony remains deep underground with minimal activity and few defenders at the entrance. At night, everything changes: workers emerge to forage, excavate soil, and defend the nest aggressively. Their primary defense is spraying formic acid, which has a noticeable odor when disturbed. This means daytime colony maintenance is relatively safe, but avoid disturbing the nest after dark when defenders are active. Workers forage solitarily over many meters and navigate visually, they can even be found abroad on moonless nights. They are not particularly aggressive toward keepers during the day but can deliver a startling spray if provoked at night.

Establishing Wild Colonies

If you obtain a wild-caught colony, be aware that N. carazzii has a patchy distribution even in its native Australia. These ants are challenging to find and collect because of their nocturnal habits and deep nests. When establishing a wild colony, replicate their natural conditions as closely as possible: deep nesting space, large entrance, high humidity, and quiet dark location. Expect the colony to be initially stressed and possibly reluctant to forage during the day. Be patient, they may take several weeks to establish a normal rhythm in captivity. Do not disturb the nest frequently during the founding phase.

Frequently Asked Questions