Formica spatulata

Formica spatulata

Formica spatulata is a North American ant species belonging to the Formica microgyna species group. Workers are easily recognized by their distinctive spoon-shaped (spatulate) hairs covering the pronotum and other body surfaces, which sets them apart from most other Formica species. Workers measure around 4-6mm with queens only slightly larger than the largest workers, a characteristic of the microgyna group. The head and mesosoma have abundant erect hairs, while the scape and tibiae lack erect hairs except for a row of bristles underneath ^[1].

This species is likely a temporary social parasite, meaning the queen invades a colony of another Formica species, kills the host queen, and uses the host workers to raise her first brood until her own workers emerge. The host species remains unknown. Found across the northern United States and southern Canada, these ants inhabit transition environments between boreal and temperate zones ^[2][3].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to North America, found throughout the northern United States and into southern Canada (Saskatchewan, Manitoba, Montana, Wyoming, South Dakota). Inhabits transition environments between boreal forest and temperate zones ^[2][3][1].
• Colony Type: Likely temporary social parasite of another Formica species. The queen invades a host colony, kills the host queen, and uses the host workers to raise her brood until her own workers take over. This is typical of the microgyna species group ^[1].
  • Colony: Monogyne
  • Queen: Temporary parasitic
• Size & Growth:
  • Queen: Approximately 5-7mm, only slightly larger than the largest workers ^[1]
  • Worker: 4-6mm ^[1]
  • Colony: Unknown for this specific species, but related microgyna group species typically reach several thousand workers
  • Growth: Moderate, typical for Formica species
  • Development: Estimated 6-8 weeks at optimal temperature based on related Formica species (Development time is inferred from genus-level data for Formica species. Temperature around 20-24°C supports optimal development.)
• Antkeeping:
  • Temperature: Keep nest area at 20-24°C. A gentle temperature gradient allows ants to regulate their own conditions. Room temperature in this range is typically suitable ^[1].
  • Humidity: Moderate humidity around 50-60%. Keep nest substrate slightly moist but not waterlogged. These ants prefer drier conditions compared to many forest-dwelling ants.
  • Diapause: Yes, as a temperate species, colonies require a winter rest period. Reduce temperature to 5-10°C for 3-4 months during winter, mimicking natural seasonal cycles ^[1].
  • Nesting: Natural nests are typically under stones or in soil. In captivity, a standard formicarium with soil or plaster chambers works well. Provide a dark nesting area with moderate humidity. Y-tong nests or naturalistic setups with flat stones simulate their natural preferences ^[1].
• Behavior: Workers are active foragers that search for honeydew, nectar, and small insects. They are not particularly aggressive but will defend the nest if threatened. Workers are medium-sized and can climb smooth surfaces, though escape prevention with standard barriers is usually sufficient. They exhibit typical Formica behavior with well-organized colony structure ^[1].
• Common Issues: temporary parasitism makes founding difficult, queens need a host colony to establish, which is challenging in captivity, colonies may fail if the host species is not available or compatible, winter diapause is essential, colonies that are not hibernated properly often decline, slow initial growth during the parasitic founding phase before workers emerge, queens are difficult to locate since they parasitize existing colonies rather than founding independently

Understanding Temporary Social Parasitism

Formica spatulata belongs to the microgyna species group, members of which are temporary social parasites. This means the queen does not found a colony alone like most ants. Instead, after mating, she must locate and invade an established colony of another Formica species. She enters the host nest, kills or replaces the host queen, and uses the existing host workers to raise her first brood. Once her own workers emerge, they gradually replace the host workforce ^[1].

For antkeepers, this presents a unique challenge. You cannot simply set up a founding queen in a test tube. The queen needs host workers to survive. Some keepers have success by introducing a newly mated queen to a small colony of a compatible Formica species (often related species like Formica fusca or other Formica). The process is delicate and success rates vary. This parasitic requirement makes F. spatulata more suitable for experienced antkeepers who understand social parasitism ^[1].

Housing and Nest Setup

Once established, these ants do well in standard formicarium setups. They prefer nesting in soil or sandy substrates with moderate moisture. A naturalistic setup with a soil chamber and a connected outworld for foraging works well. You can also use Y-tong (acrylic) nests with appropriate chamber sizes for their worker size of 4-6mm.

Provide a dark nesting area, these ants prefer dim conditions and will often nest in the darker portions of a multi-chamber setup. Include a water tube for humidity and ensure the nest substrate stays slightly moist but never soggy. An outworld with a foraging area allows workers to hunt for prey and collect honeydew ^[1].

Feeding and Diet

Like other Formica species, these ants are omnivorous with a preference for sweet liquids and protein. Workers collect honeydew from aphids and will readily accept sugar water, honey, or nectar. For protein, offer small insects like fruit flies, small crickets, or mealworms. They are active foragers and will readily hunt prey in the outworld.

Feed protein sources 2-3 times per week, and keep a constant supply of sugar water or honey available. Remove uneaten prey after 24-48 hours to prevent mold. A varied diet supports colony growth and health ^[1].

Seasonal Care and Hibernation

As a temperate species native to northern North America, Formica spatulata requires a winter dormancy period. In autumn, as temperatures drop, the colony will become less active. Reduce the temperature gradually to around 5-10°C and maintain this for 3-4 months, typically from late October through February in the Northern Hemisphere.

During hibernation, keep the colony in a cool location like an unheated garage or basement. The nest should remain slightly moist but not wet. Do not feed during hibernation. In spring, gradually warm the colony back to room temperature and resume normal feeding. Colonies that are not properly hibernated often fail to thrive in subsequent seasons ^[1].

Frequently Asked Questions

References