Aphaenogaster ichnusa

Aphaenogaster ichnusa

Aphaenogaster ichnusa workers are small ants with a brown-yellow to dark brown body and a characteristically smooth, shiny head ^[1][2]. They have short, triangular propodeal spines, often reduced to just a small tooth, compared to their close relative A. subterranea ^[1]. These ants inhabit Mediterranean regions of West Europe, including France, Italy, and Spain, particularly on islands like Sardinia, Corsica, and Sicily ^[1][3]. In nature, they nest under rocks in shady forests with plenty of leaf litter and humidity ^[3].

What makes this species particularly interesting is its flexible social structure. While many colonies contain just one queen, researchers have found up to five dealate queens living together in some nests, suggesting they can tolerate multiple queens ^[3]. Additionally, this ant was only elevated to full species status in 2019,having been previously considered a subspecies of A. subterranea ^[1].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Mediterranean climate regions of France, Italy (including Sardinia, Corsica, Sicily), and Spain ^[1][3]
• Colony Type: Facultatively polygynous, colonies may have one queen or up to five queens working together ^[3]
  • Colony: Monogyne, Polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 6-8mm
  • Worker: Approximately 4-5mm (head length ~1mm) ^[1]
  • Colony: Unknown, likely moderate (several hundred workers) based on genus patterns
  • Growth: Moderate
  • Development: Estimated 8-12 weeks at 24°C (Development time not directly measured, estimate based on typical Aphaenogaster patterns. Nanitic workers may emerge slightly faster.)
• Antkeeping:
  • Temperature: 20-25°C during the activity season, with a winter cooling period to 10-15°C
  • Humidity: Moderate to high, keep the nest substrate damp but not waterlogged, mimicking shady forest floors with leaf litter ^[3]
  • Diapause: Yes, requires a winter rest period from approximately November to February simulating Mediterranean winter
  • Nesting: Naturalistic setups with flat stones and leaf litter, or Y-tong/plaster nests with moderate humidity retention ^[3]
• Behavior: Crepuscular foragers that are most active at dusk, scavengers and predators that also tend root aphids for honeydew, generally calm but fast-moving ^[3]. Their small size means excellent escape prevention is essential.
• Common Issues: small size (4-5mm) means they can escape through tiny gaps in mesh or around lids., require consistent humidity in the nest substrate without waterlogging to prevent mold., crepuscular activity means most foraging happens at dusk, so daytime checks may miss important colony activity., slow growth if kept below optimal temperatures.

Nest Preferences and Setup

In nature, Aphaenogaster ichnusa nests under rocks and flat stones in shady forest habitats with plenty of leaf litter and humidity ^[3]. They are not truly subterranean but prefer the interface between soil and surface debris.

For captive colonies, a naturalistic setup with flat stones, leaf litter, and a soil-sand mix works well. Alternatively, a Y-tong or plaster nest with moderate humidity retention and chambers sized to their small scale (tight spaces rather than open rooms) is suitable. Provide a humidity gradient with one side slightly damper than the other so the colony can self-regulate.

Feeding and Diet

These ants are primarily predators and scavengers, but they also engage in trophobiosis, tending root aphids to collect honeydew ^[3]. In captivity, offer a varied diet including small live or freshly killed insects (fruit flies, small crickets, mealworm pieces) and sugar sources such as honey water or sugar water.

Because they are small, cut prey into appropriately sized pieces. They may also accept seeds and other plant material as part of their scavenging behavior. Ensure protein is available regularly to support brood development.

Temperature and Seasonal Care

Aphaenogaster ichnusa inhabits Mediterranean climate zones with warm, dry summers and mild, wet winters ^[3]. Keep active colonies at 20-25°C during spring through autumn. Provide a heating cable on one side of the nest to create a gentle gradient, allowing the ants to thermoregulate.

These ants require a winter diapause period. From approximately November to February, cool the colony to 10-15°C and reduce feeding. Maintain slight humidity during this period to prevent desiccation, but the colony will be largely inactive.

Behavior and Activity Patterns

These ants show minimal daytime foraging in shady habitats, with workers becoming active primarily at dusk ^[3]. They forage within the leaf litter layer and in small spaces under rocks rather than on open surfaces.

While their close relative A. subterranea is known for tool use (dropping debris into liquid food to soak it up), this behavior has not been explicitly confirmed for A. ichnusa, though it may share similar foraging intelligence. They are generally peaceful and not aggressive, but their small size and speed make them skilled escape artists.

Colony Structure and Queen Number

Unlike many ant species that strictly limit colonies to one queen, Aphaenogaster ichnusa shows flexibility. Researchers have documented colonies containing up to five dealate queens living together ^[3]. This suggests the species is facultatively polygynous, able to function with either single or multiple queens.

For keepers, this means you may be able to introduce additional queens to an established colony, though this should be done carefully and with observation for aggression. Single-queen colonies are also common and perfectly viable.

Frequently Asked Questions

References