Nylanderia fulva

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Native to central South America (Brazil, Argentina, Paraguay). Invasive in southeastern United States (Texas, Florida, Louisiana, Mississippi, Alabama, Georgia), Caribbean islands, and Colombia. Found in diverse habitats from urban areas to agricultural fields, often nesting under objects, in leaf litter, soil, rotting wood, and potted plants ^[4][2][5].
• Colony Type: Polygynous (multiple queens per colony) and polydomous (multiple interconnected nests). Colonies can contain 15-20 queens under each landscape object, with up to 300 queens documented in single nests in the invasive range. Forms supercolonies in invasive areas with no intraspecific aggression between colonies ^[1][6][7].
• Size & Growth:
  • Queen: Approximately 4-5 mm, inferred from Nylanderia genus patterns
  • Worker: ~2 mm ^[1]
  • Colony: Extremely large, colony fragments range from 451 to 27,518 individuals with average fragments containing ~2,833 workers,602 larvae,802 pupae,35 males, and 21 queens ^[8]
  • Growth: Fast, development from egg to adult takes 23-50 days at 27°C and 80% humidity ^[8]
  • Development: 23-50 days at optimal conditions (27°C,80% RH). Mean: egg development 16.2 days, larval 10.8 days, pupal 12.2 days ^[8] (Development is temperature-dependent. Peak brood production occurs in spring and fall. Colonies can grow extremely large due to multiple queens and polydomous structure.)
• Antkeeping:
  • Temperature: Keep at 24-28°C. Foraging occurs between 10-37°C, with peak activity around 28°C. Reduced foraging below 19°C, and they become largely inactive below 10°C ^[1][9][8].
  • Humidity: Moderate to high humidity (60-80%). Colonies thrive in moist environments and nest in areas that retain moisture. Provide water access but avoid waterlogging the nest ^[1].
  • Diapause: Partial dormancy in winter. Worker numbers drop significantly in summer (394 per colony) compared to winter (1,933 per colony). Queen numbers also fluctuate seasonally, higher in winter/spring (15-17) versus summer/fall (2-3). Populations decrease dramatically in winter but colonies remain active ^[1][10].
  • Nesting: Use test tubes or nests made of Y-tong, plaster, soil, or 3D-printed materials. They nest under and within almost any object, provide multiple chambers and hiding spots. Colonies relocate readily when disturbed, so provide secure, dark nesting sites. They prefer nests in pine bark over aromatic cedar ^[9][1].
• Behavior: Highly active foragers with characteristic erratic 'crazy' movement patterns. They form long foraging trails and use mass recruitment to dominate food sources. Workers are non-aggressive toward conspecifics even from distant colonies (supercolonial structure in invasive range). They can be aggressive toward other ant species and have been documented winning 93% of contested food encounters against fire ants. They produce formic acid for defense and can detoxify fire ant venom through specialized grooming behavior. Workers can survive 98% exposure to fire ant venom when able to perform acidopore grooming. They are excellent climbers and may escape if not properly contained. They are attracted to electrical equipment and can cause short circuits.
• Common Issues: invasive species, illegal to keep in many jurisdictions and should never be released ^[15], supercolonial structure means colonies can become enormous, ensure you can house thousands of workers ^[6], they readily relocate nests when disturbed, secure housing is essential ^[1], attracted to sweet foods and protein, can become pestering if they escape ^[9], can transmit pathogens, maintain strict hygiene if keeping this species ^[2], very small size means escape prevention must be excellent, they can squeeze through tiny gaps ^[16], colony fragments as small as 451 individuals can establish new nests with multiple queens ^[8], queens can be accepted by unrelated colonies, colony fusion is possible ^[6]

Housing and Setup

Nylanderia fulva requires secure housing due to their small size and tendency to escape. Use test tubes for founding colonies or small setups with Y-tong, plaster, or 3D-printed nests for established colonies. They prefer moist environments but not waterlogged conditions, a water tube for humidity is essential. Because they are polydomous (multiple nest sites), providing multiple connected chambers mimics their natural structure. They readily relocate when disturbed, so place the setup in a quiet location with minimal vibration. Escape prevention is critical, apply Fluon or similar barriers to all openings. They accept a wide range of nest materials but studies show they prefer pine bark over aromatic cedar mulches. Provide a dark nesting area as they prefer concealed spaces. Outworld setup should include multiple feeding stations since they use mass recruitment to food sources ^[9][1].

Feeding and Diet

These ants are omnivorous with strong preferences that shift seasonally. In spring through fall, they prefer protein sources (tuna, beef, insects). In winter, they strongly prefer carbohydrate sources (sucrose, honey). They are highly attracted to sweet foods, studies show mint apple jelly and hot dog slices were most favored year-round. They also actively tend hemipteran insects (aphids, scales, mealybugs) for honeydew, and will farm these insects if provided. Protein comes from hunting small insects and arthropods. They require both liquid carbohydrates (sugar water, honey) and solid protein (insects, meat) for balanced nutrition. Feed protein 2-3 times weekly in warm months, reduce to once weekly in winter while offering sugar water constantly. Remove uneaten protein within 24 hours to prevent mold ^{[8][1][11][9]}.

Temperature and Seasonal Care

Maintain temperatures between 24-28°C for optimal colony development. They are active across a wide range (10-37°C) but peak foraging occurs around 28°C. Foraging drops significantly below 19°C and they become largely inactive below 10°C. In winter, colonies contract, worker numbers drop from ~1,933 in winter to ~394 in summer. Queen numbers also fluctuate from 15-17 per colony in winter/spring to just 2-3 in summer/fall. Brood production peaks in spring and fall. While they don't require true hibernation, cooler winter temperatures (18-22°C) will slow activity and reduce feeding. Avoid temperatures below 10°C for extended periods. A gentle heat gradient allows workers to self-regulate their temperature preference ^{[1][10][8][9]}.

Colony Structure and Reproduction

N. fulva colonies are polygynous (multiple egg-laying queens) and polydomous (multiple interconnected nests). A single colony fragment can contain 15-20 queens, with up to 300 queens documented in invasive populations. Each queen can lay approximately 0.25 eggs per hour. Colonies produce sexuals (males and new queens) seasonally, male production peaks in fall and winter. New colonies spread primarily through budding (nest fission) rather than nuptial flights, no mating flights have been observed in the field. Colonies can fragment and relocate readily, with new fragments capable of establishing with just a few queens and workers. This social structure (supercoloniality) means there is no aggression between workers from different colonies in the invasive range, they will even fuse colonies when brought together ^{[6][10][8][1]}.

Defense and Unique Behaviors

This species has remarkable defensive adaptations. Workers produce formic acid in their acidopore (special gland at the gaster tip) and can perform 'acidopore grooming', a stereotyped behavior where they apply formic acid to body parts exposed to fire ant venom. This detoxification allows 98% survival when exposed to fire ant venom (compared to 48% when denied access to formic acid). They can displace the aggressive red imported fire ant in 93% of contested encounters. Workers are also attracted to electrical equipment where large accumulations cause short circuits and equipment failure. When attacking, they deposit formic acid which causes a burning sensation often mistaken for a sting. They build long foraging trails and use recruitment pheromones from both Dufour's gland and venom gland to coordinate mass attacks on food sources or enemies ^{[12][1][13][14]}.

Legal and Ethical Considerations

Nylanderia fulva is a significant invasive species in the southeastern United States and several Caribbean islands. It is prohibited from release in many areas and should never be kept where it is not already established. The species has caused extensive ecological damage in its invasive range, displacing native ant species and other invertebrates. It also facilitates agricultural pests by protecting honeydew-producing insects. Before acquiring this species, verify that keeping it is legal in your jurisdiction and that you can provide appropriate containment to prevent escape. Responsible antkeeping requires never releasing invasive species into the wild, even if they were originally captive-bred ^[15][3][5].

Frequently Asked Questions

Report an Issue

The current care sheet is based fully on literature. See inconsistencies, or something that's incorrect? Please report here, it will be resolved after review from an admin. Contributing to the blogs tab also helps providing information, to make us be able to further improve the caresheets. Thank you for your support!

References