Myrmica xavieri

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Mountain regions of central Spain (Teruel and Soria provinces) at 1,500–1,800 m elevation. Nests in soil under stones in open pine forest (Pinus sylvestris) with moist soil, and in well-trampled grass on mountain passes near pine forest ^[1][3].
• Colony Type: Unconfirmed – colony structure has not been documented. Based on related Myrmica in the lobicornis-group, likely single-queen, but this needs confirmation.
• Size & Growth:
  • Queen: Size data unavailable. Only head measurements are known, which do not represent total body length. Inferred to be similar to other Myrmica but exact size unknown.
  • Worker: Size data unavailable. Only head measurements are known, which do not represent total body length. Inferred to be similar to other Myrmica but exact size unknown.
  • Colony: Unknown – no colony size data available. Based on related Myrmica species, likely up to several hundred workers.
  • Growth: Moderate – typical for Myrmica genus
  • Development: Estimated 6–10 weeks based on typical Myrmica development at cool temperatures (around 18°C) (Development time is inferred from genus-level data since species-specific studies are not available)
• Antkeeping:
  • Temperature: Keep cool – aim for 15–20°C. This is a high-altitude mountain species from Spain. Avoid heat and direct sunlight. Overheating is a serious risk ^[1].
  • Humidity: Keep the nest substrate moist but not waterlogged. In nature, they nest in moist soil under stones in pine forests. Provide a damp area and good ventilation ^[1].
  • Diapause: Yes – as a temperate mountain species, colonies need a winter rest period. Gradually lower temperature to 5–10°C for 3–4 months (typically November–February).
  • Nesting: Use a test tube setup or a naturalistic formicarium with moist soil. Replicate their natural nesting under stones. Y-tong or plaster nests with soil chambers work well.
• Behavior: Workers are moderately active and forage for small insects and honeydew. They have a functional stinger but are not aggressive toward keepers. Escape risk is moderate – use standard barriers. Propodeal spines are mostly for defense against other ants.
• Common Issues: overheating is the biggest risk – keep colony cool (15–20°C) at all times, colony structure unknown – start with a single queen to avoid conflicts, no specific colony size data exists – monitor growth and adjust care accordingly, as a recently described species (2008), captive breeding information is limited, cool temperature requirements may conflict with room temperature in warm climates – consider cooling options

Origin and Discovery

Myrmica xavieri was formally described in 2008 by Radchenko, Elmes, and Savolainen. It was discovered in the mountains of central Spain – the Sierra de Albarracín in Teruel province (1,630 m elevation) and the Sierra de Urbión in Soria province (1,500 m). The species is named after Spanish myrmecologist Professor Xavier Espadaler ^[1].

The ant is thought to be a relict species isolated in the Iberian Peninsula during the Pleistocene ice ages. It shows a mix of traits from different species groups (lobicornis and schencki), suggesting it may represent a distinct evolutionary lineage. Its known distribution is extremely limited – only these two mountain areas in Spain ^[1].

Natural Nesting Habitat

In the wild, Myrmica xavieri nests in soil under stones. The holotype nest was in open pine forest (Pinus sylvestris) with moist soil at 1,630 m. The paratype nest was in well-trampled grass on a mountain pass at around 1,500 m, also near pine forest ^[1].

To replicate this in captivity, use a moist soil substrate in a test tube or a naturalistic formicarium. Keep the substrate damp but not saturated, with some drier areas so ants can choose. Placing flat stones on the soil surface mimics their natural nesting situation.

Temperature Requirements

This mountain species prefers cool conditions. Keep the nest at 15–20°C – significantly cooler than room temperature for most people. In their natural habitat at 1,500–1,800 m, temperatures are much lower than in lowland Spain ^[1].

Avoid any direct heat sources. Overheating is the most common mistake with this species. If your room temperature runs above 22°C, you'll need to cool the nest – consider a cool basement or a dedicated ant fridge. Monitor temperature carefully during summer.

Feeding and Diet

Like other Myrmica, Myrmica xavieri is omnivorous. Feed small live insects (fruit flies, small crickets, mealworms) for protein, and provide sugar water or honey for carbohydrates. In the wild, they likely forage for small invertebrates and tend aphids for honeydew.

Offer protein 2–3 times per week, removing uneaten prey after 24 hours. Keep a constant supply of sugar water. Since captive data is limited, observe your colony's preferences and adjust accordingly.

Winter Care and Diapause

As a temperate mountain species, Myrmica xavieri requires a winter rest period. From around November to February, gradually lower the temperature to 5–10°C and keep it there for 3–4 months. This mimics the natural seasonal cycle in their high-altitude habitat.

Place the colony in a cool garage, basement, or a dedicated ant fridge. Keep the nest substrate slightly moist during hibernation – don't let it dry out completely. In spring, slowly return to normal temperatures.

Appearance and Identification

Workers of Myrmica xavieri are reddish-brown and have several distinct features: long, straight, divergent propodeal spines, an antennal scape strongly angled at the base with a small vertical lobe, and a clypeus without a medial notch (unlike many related species). The body has coarse ridges (rugae) and is fairly hairy ^[1].

Queens are similar but have coarser sculpture, especially on the trunk and waist. Males are dark brown to black with very long antennal scapes – longer than in most other Myrmica. Males also lack the medial notch on the clypeus ^[1].

Frequently Asked Questions

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References