Formica aserva

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to North America from Newfoundland to Yukon and Alaska to New Mexico ^[2]. Inhabits prairies, sagebrush scrub, forests, and disturbed areas ^[7][8].
• Colony Type: Facultatively polygynous, colonies can have multiple queens ^[9][7]. As a facultative slavemaker, colonies may have enslaved Formica workers but can survive without them ^[4].
• Size & Growth:
  • Queen: Size data unavailable, inferred from Formica genus to be around 7-9 mm
  • Worker: 4.0-6.0 mm ^[1]
  • Colony: Up to several hundred workers ^[10]
  • Growth: Moderate
  • Development: Unknown, no specific data available (Development timeline not documented in research, inferred from genus patterns.)
• Antkeeping:
  • Temperature: Keep warm, roughly 20-24°C, based on thermophilic nature ^[7]. Use a heating cable to create a gradient.
  • Humidity: Keep nest substrate consistently moist but not waterlogged, as they nest in dead wood ^[7].
  • Diapause: Yes, requires winter diapause of 3-4 months at 5-10°C, inferred from northern range ^[11].
  • Nesting: Prefers stumps and decaying wood, provide naturalistic setup with rotting wood or Y-tong/plaster nest ^[7][11].
• Behavior: Aggressive and active, workers have task groups with high fidelity ^[12]. Defend territory vigorously and conduct raids on other colonies ^[5]. Escape risk is moderate due to worker size (4-6 mm), use standard barriers.
• Common Issues: slave dependency, colonies may struggle without access to host species for raiding ^[4], cold sensitivity, thermophilic nature means they decline in cool conditions below 18°C ^[7], colony establishment, founding queens must parasitize host colonies, which can fail ^[2], disturbance intolerance, prefer stable nesting sites ^[8], parasitic fungus, Laboulbenia formicarum can infect workers ^[15]

Colony Founding and Slave-Making

Formica aserva is a facultative slavemaker, it can function with or without enslaved workers, but typically maintains some enslaved Formica from species like F. fusca or F. argentea ^[4]. The queen invades a small host colony, eliminates the host queen, and takes over the nest and brood ^[2]. Workers from stolen pupae accept the intruding queen. Once numerous, they raid other colonies for more slaves, involving long foraging columns and serious fighting ^[5]. In captivity, establish colonies by introducing a founding queen to an established host colony.

Housing and Nest Preferences

In the wild, Formica aserva prefers nesting in stumps and decaying wood (decay classes 3-4) rather than downed debris ^[7]. They construct thatched nests using plant material ^[11] and prefer high-insolation disturbed areas ^[8]. For captivity, provide a naturalistic setup with rotting wood pieces or a Y-tong/plaster nest with narrow chambers. Include thatch material for manipulation and a moisture gradient.

Feeding and Diet

Workers are generalist feeders with task groups: honeydew collectors (smaller workers), nest builders, and protein foragers (larger workers) ^[12]. They tend aphids for honeydew, with mutualistic relationships to aphid species like Aphis asclepiadis ^[13]. In captivity, provide sugar water, protein sources like mealworms, and live prey. They defend aphid farms against ladybird beetles ^[6].

Temperature and Seasonal Care

This is a thermophilic species requiring warm conditions ^[7]. Keep nest temperatures around 20-24°C with a heating gradient. As a northern species, it requires winter diapause of 3-4 months at 5-10°C ^[11]. Nuptial flights occur from mid-June to late July in early morning at cool temperatures.

Behavior and Defense

Formica aserva is aggressive and mound-building, with workers showing high task fidelity ^[12]. They defend territory vigorously and conduct raids with serious fighting ^[5]. Defense mechanism is spraying formic acid, typical of Formicinae. They are disturbance specialists, found in human-altered habitats ^[8][14].

Common Problems in Captivity

Challenges include slave dependency, cold sensitivity, difficult colony establishment, disturbance intolerance, and parasitic fungus ^[4][7][15]. Proper hibernation is essential for long-term health. Watch for Laboulbenia formicarum infections.

Frequently Asked Questions

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References