Pheidole rugosula

Pheidole rugosula

Pheidole rugosula is a small ant species known for its distinctive major workers (soldiers) that have oversized, rectangular heads. Workers are 2-4mm, with majors significantly larger than minors. The species has a reddish-brown to dark brown coloration. Originally described from Australia, this ant has been introduced to New Zealand where it is considered an invasive species. As a member of the tribe Attini, these ants are fungus farmers in the wild, though captive colonies readily accept protein and sugar sources. The species shows strong preference for protein baits and is most active at temperatures between 20-30°C.

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Native to Australia, introduced to and established in New Zealand. In its introduced range, it prefers urban areas, port regions, and disturbed habitats. Found on vegetation, buildings, and broken surfaces in New Zealand ^[1][2].
• Colony Type: Polygynous (multi-queen) colonies typical for Pheidole species. Colonies can grow large with multiple queens working together.
  • Colony: Polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Estimated 6-8mm based on genus typical size
  • Worker: 2-4mm (minors 2-3mm, majors 3-4mm)
  • Colony: Estimated several thousand workers based on genus patterns
  • Growth: Moderate
  • Development: Estimated 6-8 weeks at optimal temperature based on related Pheidole species (Development time typical for tropical/subtropical Myrmicinae)
• Antkeeping:
  • Temperature: Keep between 22-28°C. Research shows activity peaks between 20-30°C, so a warm setup works well ^[3]. Avoid temperatures below 15°C for extended periods.
  • Humidity: Moderate humidity around 50-70%. These ants tolerate drier conditions better than many Myrmicinae. Provide a water tube but avoid overly damp nests.
  • Diapause: Not required in the typical sense. New Zealand populations experience cooler winters but the species is not documented to enter true diapause. Keep at room temperature year-round with slight cooling in winter acceptable.
  • Nesting: Will readily accept test tubes, Y-tong nests, or plaster nests. They do well in dry to moderately humid setups. Provide connecting tubes to an outworld for foraging.
• Behavior: Generally peaceful but majors will defend the colony aggressively if threatened. Workers are active foragers with strong preference for protein foods. They are not aggressive toward humans and rarely sting. Escape risk is moderate, use standard barrier methods but no special escape prevention needed beyond standard care.
• Common Issues: colonies may decline if fed only sugar, protein is essential for colony growth, overheating above 30°C can stress or kill colonies, wild-caught colonies from New Zealand may be polygynous and difficult to establish as single-queen colonies, test tube setups work well but ensure water tubes are not overfilled to prevent flooding

Housing and Nest Setup

Pheidole rugosula adapts well to various captive setups. Test tube arrangements work excellently for founding colonies, use a standard test tube with a water reservoir plugged with cotton. Once the colony reaches 50+ workers, you can connect multiple test tubes or transition to a Y-tong (acrylic) nest. Plaster nests also work well, providing the moderate humidity this species prefers. These ants do not require high humidity like some tropical species, making them forgiving for beginners. Ensure the outworld is escape-proof with a barrier of fluon or petroleum jelly.

Feeding and Diet

This species shows strong preference for protein foods. In studies, P. rugosula consistently chose protein baits over sugar or combination baits ^[4]. Offer protein sources 2-3 times per week: small insects like fruit flies, mealworms, or cricket pieces. Sugar water, honey, or commercial ant nectar can be offered weekly for energy. Unlike some Attini tribe members that cultivate fungus, P. rugosula is omnivorous and readily accepts both protein and carbohydrates. Remove uneaten protein within 24 hours to prevent mold.

Temperature Management

Keep your colony in the 22-28°C range for optimal growth and activity. Research shows these ants actively forage between 20-30°C ^[3]. Room temperature (around 22-24°C) is typically ideal without additional heating. If your home is cooler, a heating cable on one side of the nest can create a temperature gradient. Avoid temperatures above 30°C as this causes stress, and do not allow temperatures to drop below 15°C for extended periods. A slight winter cooling to 18-20°C is acceptable but not required.

Colony Structure and Growth

Pheidole species are polygynous, meaning colonies typically have multiple queens. This leads to faster colony growth initially as multiple queens produce workers simultaneously. Expect the founding phase to last 4-6 weeks before the first workers (nanitics) emerge. Colonies can reach several thousand workers over several years. The presence of major workers (soldiers) with their distinctive large heads is a hallmark of Pheidole, these majors defend the colony and help process larger food items. Do not disturb the queen during the founding phase, queens are claustral and seal themselves in to raise their first brood.

Legal and Ethical Considerations

Pheidole rugosula is an introduced species in New Zealand and is considered invasive. If you are keeping this species in New Zealand, do not release any ants into the wild as they could establish and impact native ecosystems. In Australia, it is a native species so no restrictions typically apply. Always check your local regulations regarding ant keeping, and never release captive colonies regardless of location. ^[1]

Frequently Asked Questions

References