Lasius emarginatus (Two-Colored Garden Ant)
Introduction
Lasius emarginatus, commonly known as the Two-Colored Garden Ant or the European Rock Ant, is one of the most aesthetically pleasing and adaptable species in the Lasius genus. While many of its relatives are uniform black or yellow, Lasius emarginatus stands out with its beautiful bi-colored appearance, featuring a reddish-brown thorax that contrasts sharply with its dark head and gaster. Found throughout Central and Southern Europe, this species is a frequent inhabitant of both natural rocky landscapes and urban environments, often nesting in the walls of old stone buildings or under pavement.
For ant keepers, Lasius emarginatus is a fantastic "next step" after starting with the more common Lasius niger. They are just as hardy and easy to care for, but they are significantly faster, more agile, and visually more interesting. They are known for their high activity levels and their ability to thrive in a variety of nest types, making them an excellent choice for hobbyists who want a bustling, colorful colony that is resilient enough to handle a few beginner mistakes.
Taxonomy and Distribution
Lasius emarginatus belongs to the subfamily Formicinae and the subgenus Lasius sensu stricto. It is closely related to the ubiquitous Lasius niger, but it is distinct both in its morphology and its preferred habitat. While L. niger is often found in open fields and gardens, L. emarginatus has a strong preference for "stony" environments, earning it the nickname "the wall ant" in some regions.
Their distribution is primarily European, with a range that extends from Spain and Italy up into Germany and Southern England. They are particularly common in the Mediterranean region, where they have adapted to the warmer, drier conditions. Their ability to nest in human-made structures has allowed them to become one of the most common urban ants in Central Europe, often seen running along garden walls and sidewalks with surprising speed.
Physical Characteristics
Lasius emarginatus is a monomorphic species, with workers typically measuring between 3.5mm and 5mm in length. Their most striking feature is their coloration: the head and gaster are a dark, polished brown or black, while the thorax (mesosoma) is a distinct reddish-brown or "brick red." This two-tone pattern makes them easy to identify even with the naked eye. Their bodies are slightly more slender and their legs a bit longer than those of Lasius niger, reflecting their more agile, "runner" lifestyle.
They possess large, sensitive eyes and a keen sense of smell, which they use to navigate and find food. Like all Formicine ants, they do not have a stinger but have a well-developed acidopore for spraying formic acid. The queen is a robust, impressive ant, typically reaching 8-10mm in length. She is usually a solid dark brown, though some queens may show a slight reddish tint on the thorax under bright light. She is a highly productive layer, capable of founding large colonies that can live for many years.
Colony Behavior and Social Structure
Colonies of Lasius emarginatus are strictly monogynous (one queen) and can grow to be quite large, eventually numbering between 10,000 and 50,000 workers. They are incredibly active and fast-moving; a single worker can cover a surprising amount of ground in a short time. This agility is one of their primary defenses, allowing them to outrun competitors and quickly retreat to the safety of the nest.
They are highly social and communicate through a complex system of pheromones and tactile signals. They are particularly good at "tandem recruitment," where one ant leads another to a food source. In the nest, they are meticulous about brood care and maintenance. They are also known for being "wall builders," using soil and debris to create intricate structures or to seal off nest entrances, a behavior that is clearly visible in a home formicarium.
Diet and Foraging
Lasius emarginatus is a generalist omnivore with a strong preference for sugary substances. In the wild, they are frequently found tending aphids on trees and shrubs to harvest honeydew. In captivity, they require a consistent supply of carbohydrates in the form of sugar water, honey water, or specialized ant nectars. They have a high metabolism and are always on the lookout for a sweet treat.
Protein is equally essential, especially for the development of the larvae. They are opportunistic scavengers and occasional hunters, readily accepting a variety of feeder insects such as fruit flies, small crickets, and mealworms. Because they are fast and coordinated, they can quickly overwhelm small prey items. A varied diet of both sugars and proteins will ensure that the colony remains healthy and that the queen continues to produce plenty of eggs.
Life Cycle and Reproduction
The life cycle of Lasius emarginatus follows the standard egg-larva-pupa-adult progression. At optimal temperatures (22-26°C), the development from egg to worker takes about 6 to 9 weeks. Like other Formicinae, they pupate in silk cocoons. During the summer, a healthy colony will also produce winged alates (males and virgin queens), which will eventually leave the nest for their nuptial flights.
Nuptial flights typically occur on warm, humid evenings in July and August. After mating, the queen searches for a suitable nesting site—usually a small crack in a rock or wall—to begin her independent colony founding (claustral founding). She will not leave her first chamber until her first "nanitic" workers have emerged to take over the foraging duties.
Environmental Requirements
Lasius emarginatus is a hardy species that is quite tolerant of environmental fluctuations. However, to see them at their best, a temperature of 22-26°C (72-79°F) is recommended during the active months. They require a period of diapause (hibernation) during the winter, typically from November to March, at temperatures between 5°C and 10°C. This period is crucial for the queen's longevity and the colony's long-term health.
Humidity should be kept at a moderate level (around 50-60% in the nest). Because they naturally nest in stony environments, they do very well in acrylic, plaster, or Ytong nests. They appreciate a dry foraging area (outworld) with some stones or bark to climb on, which mimics their natural habitat.
Keeping Lasius emarginatus as Pets
Lasius emarginatus is often cited as one of the best "all-rounder" species for ant keeping. They are visually appealing, active, and easy to maintain. They are less aggressive than some other species but are far more engaging than the slower-moving ants. Their "two-colored" look makes them a great display ant, and their rapid growth means that the keeper is constantly rewarded with a sense of progress. Whether you are a beginner looking for your first "advanced" species or a veteran keeper who appreciates the classics, Lasius emarginatus is a fantastic choice.
Recommended Habitats
To provide the best home for your Lasius emarginatus colony, we recommend the following ANT SHACK products:
- Ant Habitat “Paris“ - This habitat is perfectly suited for the active and inquisitive nature of Lasius emarginatus. Its horizontal design and clear acrylic provide excellent visibility, allowing you to appreciate their beautiful bi-colored bodies as they go about their daily tasks.
- All-in-One Desktop Ant Habitat - A great choice for starting a Lasius emarginatus colony. The integrated outworld and secure nest area provide everything a young colony needs to thrive in a compact and easy-to-manage setup.
- Natural Ant Habitat Kit - Large - For a more realistic setup, this kit allows you to add stones and soil, recreating the "stony" environment that this species loves. It's a great way to observe their natural nesting and tunneling behaviors.