Solenopsis papuana

Solenopsis papuana - "Ant"

Solenopsis papuana is a tiny ant species native to the Papuan region (Papua New Guinea) that has spread across much of the Pacific. Workers measure approximately 1.5mm and range in color from pale yellow to brownish-yellow or even dark brown, color is quite variable in this species ^[1][2]. The species gets its 'thief ant' name from its habit of nesting in soil and leaf litter where it forages and scavenges. Queens and males have been described, with workers being monomorphic (all the same size) ^[3].

This species has become invasive in Hawaii, where it was first detected in 1967 and has since spread to multiple islands including Kauai, Molokai, Lanai, and Hawaii ^[4]. It is one of the few ant species to successfully infiltrate undisturbed mesic and wet upland forests in Hawaii, reaching high densities in soil and leaf litter ^[4]. Research has shown that suppressing these ants can increase native Hawaiian picture-winged Drosophila fly reproduction by 2.4-fold, demonstrating their significant impact on native ecosystems ^[1].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Native to Papua New Guinea and surrounding Pacific islands. Found across Fiji, Samoa, Tonga, Solomon Islands, French Polynesia, Micronesia, and has been introduced to Hawaii (1967) and possibly Australia ^[5][6][7]. In its native range, it lives in wet to mesic forests between 300-1,100m elevation, nesting under rocks or wood on the ground ^[8].
• Colony Type: Polygyne (multiple-queen) colonies can contain over 1,000 workers ^[8]. This is a ground-nesting species that spends most of its time in soil and leaf litter.
  • Colony: Optionally polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 3-4mm (estimated based on genus)
  • Worker: Approximately 1.5mm ^[1][9]
  • Colony: Up to 1,000+ workers in mature colonies ^[8]
  • Growth: Moderate, based on typical Solenopsis development patterns
  • Development: Estimated 5-7 weeks at optimal tropical temperatures (around 24-28°C) (Development time inferred from related Solenopsis species. Warm temperatures will accelerate development.)
• Antkeeping:
  • Temperature: Keep at 24-28°C, these are tropical ants that prefer warm, stable conditions. Room temperature within this range works well.
  • Humidity: Moderate to high (60-80%). Keep the nest substrate consistently moist but not waterlogged. They naturally live in forest floor environments with damp soil and leaf litter.
  • Diapause: No, these are tropical ants that do not require hibernation. Maintain warm temperatures year-round.
  • Nesting: Ground-nesting species that thrives in setups with moist substrate. Test tubes with a water reservoir work well, or a small naturalistic setup with soil/leaf litter. They prefer dark, humid enclosed spaces.
• Behavior: These ants are generalist feeders, they prey on small insects, scavenge, and tend honeydew-producing insects ^[1]. They can sting, and while their sting is described as painful in some contexts ^[10], Hawaii specimens have not caused reported stinging complaints ^[11]. Workers are active in the soil and leaf litter layer, often approaching food from underneath ^[4]. They will recruit vigorously to food baits and can defend resources using their stings ^[2]. Escape prevention is critical due to their tiny 1.5mm size, they can squeeze through very small gaps.
• Common Issues: escape prevention is critical due to tiny 1.5mm size, use fine mesh barriers and tight-fitting lids, tendency to stay in substrate means they may not be visible unless you provide proper foraging space, can form large colonies quickly, ensure adequate space as colony grows, do NOT release in non-native regions, this is an invasive species in Hawaii and Pacific islands, wild-caught colonies may carry parasites that can cause colony failure

Housing and Nest Setup

Solenopsis papuana is a tiny ground-nesting ant that requires careful escape prevention. A test tube setup with a water reservoir works well for founding colonies, use a small diameter tube since these ants are only about 1.5mm. For established colonies, a small formicarium with moist soil or plaster works nicely since they naturally nest in soil and leaf litter. Keep the nest area dark, these ants prefer dim conditions and will be most active when the setup is not in bright light. An outworld for foraging should be provided, but ensure all connections are sealed with fluon or other barrier since they can squeeze through tiny gaps. A small foraging arena is sufficient since they don't travel far from the nest ^[4].

Feeding and Diet

These ants are generalist feeders that accept a variety of foods. In captivity, they will readily take small live prey like fruit flies, pinhead crickets, and other tiny insects. They also scavenge dead insects and will consume protein-based baits. Sugar sources like honey water or sugar water are accepted, and they will tend honeydew-producing insects in their natural habitat ^[1]. Feed small amounts every 2-3 days, removing any uneaten prey after 24 hours. Their small size means even tiny prey items are appropriate, don't offer anything larger than they can handle. SPAM and peanut butter have been shown to attract them effectively in field studies ^[4].

Temperature and Seasonal Care

As a tropical Pacific species, Solenopsis papuana prefers warm temperatures in the range of 24-28°C. They do not require any diapause or winter cooling period, maintain consistent warmth year-round. Room temperature within this range is ideal. If your room is cooler, a heating cable on one side of the nest can provide a gentle warmth gradient. Avoid temperatures below 20°C for extended periods. Since they naturally live in wet to mesic forests, they appreciate humidity but the nest should not be constantly wet, aim for damp substrate rather than saturated. ^[8][1]

Behavior and Colony Dynamics

This species forms polygyne colonies with multiple queens, which can grow quite large, over 1,000 workers in established colonies ^[8]. Workers are most active in soil and leaf litter, where they forage and tend to honeydew-producing insects. They will occasionally forage up to 2 meters up tree trunks but are generally ground-dwelling ^[1]. When food is discovered, they recruit nestmates effectively and will defend resources using their stings ^[2]. They tend to approach baits from underneath, which is a distinctive foraging behavior ^[4]. The colony will establish multiple chambers in the substrate as it grows.

Legal and Ethical Considerations

IMPORTANT: Solenopsis papuana is an invasive species in Hawaii and has significant negative impacts on native arthropod populations. It should NEVER be released in non-native regions. If you no longer want your colony, do not release it outdoors, instead, freeze the colony to humanely end it or find another antkeeper who can take it. This species has also been intercepted at New Zealand borders ^[12][9], highlighting its potential to spread through human travel and trade. Responsible antkeeping means preventing any accidental release.

Frequently Asked Questions

References