Lasius brunneus - "Brown Tree Ant"
Lasius brunneus, often called the Brown Tree Ant, is a widespread ant species across Europe, identifiable by its distinctive bicolored appearance: workers typically have a lighter brownish-red head and thorax contrasting with a darker, sometimes blackish, gaster. Workers range from 2 to 4.5 mm, while queens are larger, usually between 6.5 and 8.5 mm. This species is known for its timid nature, often nesting within old or decaying wood, or under bark, and will quickly retreat when disturbed. They are primarily arboreal, meaning they prefer to live in trees, but can also be found foraging on the ground or under stones.
- Difficulty: Easy
- Origin & Habitat: Europe, North Africa, Asia (Palaearctic region) in Deciduous forests, mixed forests, urban areas with trees, often nesting in old or rotting wood, under bark, or sometimes under stones..
- Colony Type: Monogyne (single queen), rarely oligogyne (multiple queens but isolated, no brood mixing), claustral (queen seals herself in) founding.
- Size & Growth:
- Queen: 6.5-8.5mm
- Worker: 2.0-4.5mm
- Colony: Medium (several thousand, up to 74,000 workers, with a maximum of 200,000 in the wild). Medium (colonies can reach a few hundred workers by the second year) growth.
- Antkeeping:
- Temperature: Optimal nest temperature is between 21-28°C. Workers are active from early spring to late autumn, with reduced activity during hot, dry periods..
- Humidity: Moderate humidity, typically between 50-70%..
- Diapause: Required. 3-5 months at 5-10°C.
- Nesting: Prefers natural wood nests, such as decaying logs or crevices in old trees. In captivity, artificial nests mimicking these conditions (e.g., acrylic, ytong, 3D printed, or soil nests with wooden inserts) are suitable..
- Behavior: Low (towards handler, but aggressive in defending nest and food resources against other ants) aggressiveness.
- Common Issues: Humidity fluctuations, Lack of suitable nesting material (wood-mimicking), Insufficient protein supply, Stress from excessive disturbance.
Lasius brunneus is a fascinating ant species for antkeepers due to their unique arboreal habits and striking bicolored appearance. Unlike many common Lasius species, these ants are primarily found nesting within the wood of old or decaying trees, and they exhibit a somewhat timid nature, preferring to stay hidden within crevices and tunnels. This means your setup should ideally provide ample opportunities for them to explore and nest within wood-like structures, making cork or specialized wooden nests a great choice. They are known to quickly retreat when disturbed, which can make observing their behavior a bit more challenging but also adds to their mysterious charm.
A key aspect of Lasius brunneus care is understanding their diet, which heavily relies on honeydew from aphids in the wild. They have a symbiotic relationship with tree aphids, particularly Stomaphis quercus, actively tending them for their sugary excretions. In your formicarium, this translates to providing a consistent source of sugar water or honey. Alongside their sweet tooth, they also require protein from small insects, such as fruit flies, mealworms, or crickets, to support colony growth and queen egg-laying.
Colony growth for Lasius brunneus is considered medium, and a well-cared-for colony can reach several thousand workers. While typically monogyne, there have been rare instances of oligogyny observed, where multiple queens coexist in isolated parts of the nest without mixing their brood. This species requires a diapause (hibernation) period during the colder months, usually from late November to late March, at temperatures between 5-10°C. Properly managed diapause is crucial for the long-term health and growth of your colony.
Be mindful of their tendency to be 'fugitive' workers, meaning they prefer to move within sheltered areas like cracks and tunnels rather than open surfaces. This behavior highlights the importance of having a well-designed nest that offers plenty of enclosed spaces. If you're setting up an outworld, consider adding some small branches, bark pieces, or other decor to provide them with sheltered foraging paths. This shy nature also means they might be less prone to exploring open outworlds, so ensure food sources are easily accessible within their preferred foraging zones. Their nuptial flights occur earlier in the season and typically in the early part of the day, usually from June to early July in Central Europe, or even as early as May on warm days.
Frequently Asked Questions
What kind of nest is best for Lasius brunneus?
For Lasius brunneus, the ideal formicarium should mimic their natural arboreal habitat. Nests made of cork, ytong, or 3D printed designs that incorporate intricate tunnels and chambers resembling those found in wood are highly recommended. Acrylic setups can also work, especially with added wooden inserts or substrate. Remember, these Brown Tree Ants prefer sheltered spaces, so a nest with plenty of enclosed areas will make them feel secure and thrive.
What do Lasius brunneus ants eat?
Lasius brunneus primarily enjoys sugary liquids like honey water or sugar water, mirroring their natural diet of aphid honeydew. For protein, which is vital for queen egg-laying and larval development, offer small insects such as fruit flies, mealworms, or small crickets. A balanced diet of both is crucial for a healthy and growing colony of these Brown Tree Ants.
Do Lasius brunneus need hibernation?
Yes, absolutely! Like many temperate ant species, Lasius brunneus requires a period of diapause, or hibernation, to remain healthy and ensure the queen's longevity. This typically occurs from late November to late March, at cooler temperatures ranging from 5-10°C. Providing a proper hibernation cycle is essential for their long-term well-being and successful colony development.
Are Lasius brunneus good for beginners?
Lasius brunneus can be a good choice for antkeepers who have some prior experience, though they are often listed as easy. While not as straightforward as the ubiquitous Lasius niger due to their specific nesting preferences and somewhat timid behavior, they are generally hardy. If you're ready to provide a nest that caters to their arboreal nature and understand their feeding requirements, they can be a rewarding species to keep.
How large do Lasius brunneus colonies get?
A mature Lasius brunneus colony can grow to a substantial size, typically reaching several thousand workers. In their natural habitat, some large colonies have been observed with up to 74,000 workers, and even a maximum of 200,000, showcasing their potential for impressive numbers under optimal conditions.
What is the lifespan of a Lasius brunneus queen?
With proper care and a successful hibernation cycle, a Lasius brunneus queen can have a remarkably long lifespan, often living for 5 to 10 years, and some reports even suggest they can reach up to 20 years. This makes them a great species for antkeepers looking for a long-term colony to observe.
How fast do Lasius brunneus colonies grow?
Lasius brunneus colonies exhibit a medium growth rate. You can expect your colony to reach a few hundred workers by the second year, assuming consistent feeding and appropriate environmental conditions. Their growth is steady, allowing you to observe the colony's development without it becoming overwhelming too quickly.
When do Lasius brunneus have their nuptial flights?
The nuptial flights for Lasius brunneus typically occur earlier in the season compared to some other Lasius species. In Central Europe, you can expect to see alates taking flight from June to early July. However, on warm days, flights can even begin as early as May, often taking place in the early afternoon.
Are Lasius brunneus aggressive?
Lasius brunneus workers are generally considered timid towards handlers and will quickly try to escape if their nest is disturbed. However, don't let their shyness fool you; they can be quite aggressive when it comes to defending their nest and valuable food resources from other ant species in the wild.
Can Lasius brunneus infest wooden structures?
In their natural habitat, Lasius brunneus ants are known to nest in old or decaying wood, and unfortunately, they can sometimes extend this behavior to wooden structures in human dwellings. While they don't consume wood like termites, their tunneling activity can cause damage to timbers and even insulation or electrical wiring if they find their way into a property. This is why some consider them a 'house ant' in certain regions.
