Myrmica spinosior

Myrmica spinosior

Myrmica spinosior is a small to medium-sized red ant belonging to the Myrmica genus, specifically the sabuleti species complex. Workers are reddish-brown with a distinctly narrow waist and the species gets its name from its relatively long propodeal spines (the pointed projections at the back of the thorax). The species closely resembles the more common Myrmica sabuleti but can be distinguished by its wider frons (the front part of the head). This ant is native to the West Mediterranean region, being most abundant on the Iberian Peninsula and southernmost France, with populations also found in Italy, Andorra, Albania, and Turkey ^[1][2]. In the wild, they build nests under stones or in soil in mountain grassland pastures, typically at elevations between 1000-2000 meters ^[3].

One of the most interesting aspects of M. spinosior is its role as a host species for social parasites. It serves as the primary host for the rare social parasite Myrmica bibikoffi, and is likely a host for Phengaris (butterfly) parasites as well due to its close relationship with M. sabuleti ^[4][5]. The species can also be infected by the ectoparasitic fungus Rickia wasmannii, which can heavily infest workers and queens ^[6][7]. Colonies typically contain several functional queens and can grow to several hundred or even over a thousand workers ^[3].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: West Mediterranean region, primarily the Iberian Peninsula, southern France, and Italy, with populations also in Andorra, Albania, and Turkey. They inhabit mountain grassland pastures at elevations of 1000-2000m, nesting under stones or in soil ^[3][1][8].
• Colony Type: Multi-queen colonies (polygyne) with several functional queens per colony. Colonies can contain from a few hundred to over a thousand workers ^[3].
  • Colony: Polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 5-6mm, similar to other Myrmica species in the sabuleti complex
  • Worker: Approximately 4-6mm
  • Colony: Up to 1000+ workers ^[3]
  • Growth: Moderate, typical for Myrmica species
  • Development: 6-10 weeks at optimal temperature (Development time follows typical Myrmica patterns. Nuptial flights occur in July-August based on wild colony observations ^[8].)
• Antkeeping:
  • Temperature: Keep nest area at 20-24°C. These are mountain grassland ants from Mediterranean elevations, so they prefer moderate temperatures. A slight temperature gradient allows workers to regulate their conditions.
  • Humidity: Keep substrate moderately moist. These ants naturally nest under stones in soil, which tends to retain some moisture. The nest area should have damp substrate but avoid waterlogging, aim for consistently moist, not wet.
  • Diapause: Yes, these are temperate ants that require a winter rest period. Reduce temperature to around 5-10°C for 2-3 months during winter, typically from late autumn through early spring^[3].
  • Nesting: Y-tong (acrylic) nests or test tube setups work well. Provide a moisture reservoir to maintain humidity. These ants do well in formicariums with narrow chambers scaled to their worker size. Naturalistic setups with stones over soil also mimic their natural nesting preferences.
• Behavior: Myrmica spinosior workers have a functional sting and can sting defensively when threatened ^[9]. They are active foragers that search for food both on the ground and may climb vegetation. Workers are moderately aggressive compared to some Myrmica species. They are not strong escape artists but their small size means you should still use proper barriers. They form multi-queen colonies and show typical Myrmica social structure with queen tolerance ^[3].
• Common Issues: fungal infections, Rickia wasmannii can infect colonies, causing visible grayish patches on heavily infested ants ^[6][7], dry conditions, these mountain ants are sensitive to low humidity and desiccation, overheating, despite being from southern Europe, they prefer moderate temperatures rather than heat, colonies may fail if not given proper winter diapause period, small size means escape prevention is necessary, though not as critical as with tiny species

Housing and Nest Setup

Myrmica spinosior does well in standard ant keeping setups. Y-tong (acrylic) nests work excellently because they allow you to control humidity precisely. Test tube setups are also suitable, especially for founding colonies. The key is maintaining consistently moist substrate in the nest chamber while providing a dry outworld for foraging. For established colonies, a formicarium with multiple chambers gives them room to expand. These ants naturally nest under stones in soil, so a naturalistic setup with a layer of soil beneath flat stones can mimic their natural environment. Whatever setup you choose, ensure the nest chambers are appropriately sized, Myrmica workers are small enough that overly large chambers can make them feel insecure. A humidity reservoir or water tube connected to the nest helps maintain the moisture levels they need. ^[3]

Feeding and Diet

Like other Myrmica species, M. spinosior is omnivorous with a preference for protein. Offer them small insects like fruit flies, pinhead crickets, or mealworms as their primary protein source. They also readily accept sugar water, honey, or diluted syrup as an energy source. In the wild, they forage for honeydew from aphids and other small invertebrates. Feed protein-rich foods 2-3 times per week for growing colonies, and keep a constant sugar source available. Remove uneaten prey after 24-48 hours to prevent mold. These ants are active foragers, so they will readily search out and consume food items in the outworld. ^[3]

Temperature and Seasonal Care

Maintain nest temperatures between 20-24°C. These ants come from mountain grasslands in the West Mediterranean, so they prefer moderate temperatures rather than heat. Too high temperatures can stress the colony and harm brood development. A heating cable on one side of the nest can create a gentle gradient, allowing workers to move to warmer or cooler areas as needed. During winter, you must provide a diapause period, reduce temperatures to around 5-10°C for 2-3 months, typically from November through February in the Northern Hemisphere. This mimics their natural seasonal cycle and is essential for colony health. Do not feed during diapause and keep disturbance to a minimum. ^[8][3]

Colony Structure and Multi-Queen Care

Myrmica spinosior naturally forms polygyne colonies with multiple functional queens. This is unusual among ants, as many species have only one queen per colony. In captivity, you can keep multiple queens together, though initially they may squabble until they establish a hierarchy. The presence of multiple queens typically leads to faster colony growth since all queens can lay eggs. Colonies can reach 1000+ workers in the wild ^[3]. If you start with a single queen, she should establish and found a colony claustrally, she seals herself in a chamber and raises the first workers (nanitics) on her stored fat reserves without leaving to forage. After the first workers emerge, the colony enters the claustral phase and the queen resumes normal egg-laying.

Health Concerns and Parasites

One significant concern with M. spinosior is the fungal parasite Rickia wasmannii, which is known to infect this species in the wild ^[6][7][10]. This ectoparasitic fungus can infest workers and queens, with heavy infections visible as grayish patches on the ant's body. While wild colonies can tolerate low-level infections, heavily infested colonies may suffer. If you acquire a wild-caught colony, watch for signs of fungal infection. Additionally, these ants are hosts for the social parasite Myrmica bibikoffi ^[4][5]. While you likely won't encounter this parasite in captivity, it's worth being aware of their parasitic relationships. Maintain good hygiene, avoid overfeeding, and keep the nest clean to minimize disease risks.

Behavior and Temperament

Workers of M. spinosior have a functional sting and will use it defensively when the nest is disturbed ^[9]. However, they are not excessively aggressive compared to some other Myrmica species. They are active foragers and will search the outworld for food. Their multi-queen colony structure means they are generally more tolerant of conspecifics than single-queen species. Workers communicate using chemical trails and will recruit nestmates to food discoveries. The species shows typical Myrmica behavior, they are not particularly timid but also not bold to the point of being problematic. Their small size (4-6mm workers) means they can squeeze through small gaps, so ensure your setup has proper escape prevention, though they are not as prone to escaping as truly tiny ants.

Frequently Asked Questions

References