Myrmica rubra (European Fire Ant) Care Sheet & Species Profile

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1. Introduction

Myrmica rubra, commonly known as the European Fire Ant or Red Ant, is a hardy and fascinating species that occupies a unique niche in the ant-keeping world. Unlike the tropical "fire ants" of the genus Solenopsis, Myrmica rubra is a temperate species, perfectly adapted to the damp, cool woodlands and meadows of Europe and Northern Asia. They are renowned for their striking deep-red coloration, their potent stinger, and their highly social nature. In the wild, they are the undisputed masters of the undergrowth, often found nesting under mossy stones or within rotting logs. For the keeper, they offer the rare opportunity to manage a truly polygynous colony—where dozens of queens live harmoniously together in a single nest.

The "vibe" of a Myrmica rubra colony is one of ancient, steady persistence. They are not as frantic as other ants; instead, they move with a deliberate, searching pace. Because they are "semi-claustral," the founding queens are active hunters from day one, providing a unique observation window into the very earliest stages of colony life. They are moisture-lovers that thrive in lush, naturalistic setups. While their sting can be quite sharp (similar to a nettle sting), they are generally peaceful and focused on their complex social interactions. For the intermediate keeper who wants to experiment with multi-queen dynamics and a more "naturalistic" forest-floor environment, Myrmica rubra is a quintessential choice.

2. Identification & Biology

• Physical Description: These ants are a beautiful, uniform rusty-red to deep mahogany color. Their exoskeleton is noticeably rugged and "sculptured," lacking the glossy finish of many other species. They have a visible two-segmented waist and a prominent stinger at the end of the gaster.
• Size Range: Workers: 4-6mm (Monomorphic) | Queen: 7-9mm | Males: 5-6mm
• Distinguishing Features: They are easily identified by the two sharp spines on the rear of their thorax (propodeum) and their monomorphic worker caste—all workers are roughly the same size. Their movement is slower and more "deliberate" compared to the jerky, fast-paced movement of Lasius or Solenopsis.

3. Colony Structure & Dynamics

• Typical Colony Size: Mature colonies are moderately sized, typically ranging from 2,000 to 10,000 workers. However, because they are highly polygynous, they can form "super-colonies" with multiple connected nests in the wild.
• Social Structure: Strictly Polygyne. A single colony can house hundreds of fertile queens. This makes the colony extremely resilient; even if one queen dies, the colony continues to thrive.
• Worker Roles: Since they are monomorphic, workers are generalists. However, there is a clear division based on age: younger workers stay inside the nest for brood care, while older workers handle the dangerous tasks of foraging and territorial defense.
• Lifespan: Individual queens can live for 10-15 years. Workers are relatively long-lived for their size, often surviving for 1-2 years.

4. Habitat & Environmental Needs

• Natural Range: Europe and Northern Asia. They have also become a significant invasive species in parts of North America (New England and Canada).
• Temperature: Nest: 18-22°C | Outworld: 20-24°C. They do not like high heat. Overheating is one of the most common causes of colony failure for this species.
• Humidity: Nest: 70-80% (High) | Outworld: 50-70%. They are absolute moisture-lovers. They require a damp nest at all times; if the nest dries out, the brood and workers will perish quickly.
• Substrate & Nesting: Naturally ground and wood-nesting. They prefer soil with high organic content. In captivity, they thrive in gypsum or Ytong nests that can hold high levels of moisture, or in naturalistic bioactive setups.

5. Feeding & Nutrition

• Diet in the Wild: Opportunistic omnivores. They forage for honeydew from aphids, nectar, and hunt small soil invertebrates. They are particularly fond of "juicy" soft-bodied prey.
• Captive Feeding: They require a balanced diet of sugars and protein. Provide honey-water or sugar-syrup 2-3 times a week. For protein, offer fruit flies, small crickets, or chopped mealworms. Because the queens are semi-claustral, even a lone queen must be fed protein during the founding stage.
• Hydration: Essential. Beyond nest humidity, they require a constant source of drinking water in the outworld. They are poor climbers on smooth surfaces and can easily drown in open water, so use cotton-plugged feeders.

6. The Ant Shack Recommended Setup

Because Myrmica rubra are moisture-dependent, multi-queen ants that prefer cooler temperatures and have difficulty climbing smooth surfaces, we recommend the following professional gear:

• Primary Nest: All-in-One Desktop Nest - The integrated design allows for easy hydration management, which is the most critical factor for Myrmica success.
• Outworld: The Paris Series (Modern) - The wide chambers and superior hydration system of the Paris series are perfect for accommodating multiple queens and their large brood piles.
• Climate Control: Digital Hygrometer - To ensure the nest humidity stays above 70%, which is vital for this woodland species.

7. Annual Cycle: Diapause & Growth

• Hibernation (Diapause): Mandatory and long. From late October to March, the colony must be kept at 5-8°C. Without this cold period, the queens will stop laying eggs, and the colony will slowly dwindle.
• Growth Rate: Moderate. The presence of multiple queens can lead to a very rapid population increase once the colony is established, but they lack the "explosive" speed of tropical species.

8. Common Challenges & Pro-Tips

• Troubleshooting: Heat stress. If you see your Myrmica workers constantly huddling in the outworld or in the wettest part of the nest, it's likely too warm. Move the nest to a cooler location immediately. Also, they cannot climb glass or smooth plastic well; providing a textured surface or "ladder" in the outworld can help them forage more effectively.
• Expert Advice: Founding with multiple queens. When starting a new colony, you can often combine 3-5 Myrmica rubra queens together. They will cooperate to raise the first batch of workers, resulting in a much stronger and faster-growing colony than a single-queen start.