Lasius lasioides

Lasius lasioides

Lasius lasioides is a small to medium-sized ant native to the Mediterranean region. Workers measure around 0.85mm in head length, making them slightly smaller than the related Lasius brunneus. They have a distinctive coloration: the head, mesosoma, gaster, and legs are dark to medium brown, while the antenna scape, leg joints, and often the front of the clypeus are pale yellowish-brown. Queens are larger at about 1.2mm. This species is often confused with L. brunneus but can be separated by its smaller head width, longer scape, and larger distance between the torulus and clypeus ^[1].

This is a tree-dependent species found across the Mediterranean from Spain to Turkey, preferring warm, luminous forest habitats like stream valleys, pine forests, and Mediterranean bushland. It nests under tree bark, in dead wood, or under stones. The species shows interesting geographic variation, populations in Italy and Greece have longer antennae (long-scaped morph), while Spanish and Cypriot populations have shorter antennae (short-scaped morph) ^[1]. Workers are described as fugitive and non-aggressive, preferring to run along crevices in bark rather than venture into open areas.

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Mediterranean region from Morocco to Turkey, including southern France, Italy, Greece, and various Mediterranean islands. Found from sea level up to 2240m in the Moroccan Atlas Mountains. Requires the presence of trees, inhabits diverse forest types including Quercus, Pinus nigra, and Abies pinsapo forests, as well as pastures with scattered trees and urban green areas ^[1][2].
• Colony Type: Monogyne (single-queen) colonies confirmed in Greece. All Lasius species from Crete show independent colony foundation, which is typical for this genus ^[3].
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Queens approximately 1.2mm (HL 1234.9 μm, HW 1396.3 μm) ^[2].
  • Worker: Workers approximately 0.85mm (HL 848.1 μm) ^[2].
  • Colony: Colony size data not specifically documented, but typical for Lasius, likely several hundred workers ^[4].
  • Growth: Moderate, based on typical Lasius development patterns.
  • Development: 6-10 weeks estimated based on related Lasius species and Mediterranean climate conditions ^[4]. (Development timing inferred from genus-level data, specific measurements for this species not available.)
• Antkeeping:
  • Temperature: Keep at room temperature typical for Mediterranean species, around 20-24°C. Can tolerate warmer conditions given their natural range extends to North Africa and the eastern Mediterranean. Avoid temperatures below 15°C for extended periods ^[1].
  • Humidity: Moderate humidity is suitable. In nature they nest under bark, in dead wood, and under stones, conditions that are damp but not waterlogged. Provide a moisture gradient in the nest with a damp section and a drier area ^[2].
  • Diapause: Yes, as a Mediterranean species, they likely require a mild winter rest period. Reduce temperature to around 10-15°C for 2-3 months during winter, mimicking Mediterranean seasonal patterns ^[4].
  • Nesting: Prefers nesting in dead wood or under stones near trees. In captivity, a Y-tong (AAC) nest, plaster nest, or naturalistic setup with wood pieces works well. They do well in test tube setups for founding colonies. The key is providing a nest site that mimics their natural cavities under bark or in rotting wood ^[2][5].
• Behavior: Workers are described as fugitive and non-aggressive. They prefer to use runways along bark crevices rather than forage in open areas. This is a shy species that will flee rather than engage in confrontations. Escape prevention should be moderate, workers are small but not particularly known for escaping. They are not aggressive and do not sting ^[2][1].
• Common Issues: humidity control is important, overly wet conditions may cause problems in artificial nests, small colony size means they can be slow to establish, patience is needed during founding, may be confused with Lasius brunneus or L. alienus, proper identification is important, wild-caught colonies may have parasites that affect survival in captivity, they prefer established trees/wood in captivity, provide appropriate nest materials

Nest Preferences

In the wild, Lasius lasioides nests under the bark of trees, in dead logs lying on the ground, or under stones. They show a strong preference for locations near trees, whether in dense forests or pastures with just a few scattered trees. This is an arboricolous (tree-dwelling) species that rarely nests far from woody vegetation ^[2][5]. For captive colonies, provide a nest that mimics these conditions. A Y-tong (AAC) nest or plaster nest works well. You can also use a naturalistic setup with pieces of cork bark or dead wood. The nest should have a damp section to maintain moderate humidity, but avoid waterlogging. Test tube setups are suitable for founding colonies, simply provide a dark cover and keep them in a warm location.

Feeding and Diet

Like other Lasius species, these ants are omnivorous with a preference for sugary substances and protein. They tend aphids for honeydew in the wild and will also scavenge small insects. In captivity, offer sugar water or honey water as a constant food source. For protein, provide small insects like fruit flies, small mealworms, or cricket pieces. They are not aggressive foragers and prefer to exploit easy food sources. Feed them small prey items 2-3 times per week, and keep a sugar source available at all times. Given their small worker size, ensure prey items are appropriately sized. ^[4]

Temperature and Seasonal Care

As a Mediterranean species, Lasius lasioides prefers warmer conditions than many northern European Lasius. Keep them at room temperature, ideally between 20-24°C. They can tolerate higher temperatures given their range extends to North Africa and the eastern Mediterranean. During winter, provide a mild diapause period, reduce temperatures to around 10-15°C for 2-3 months. This mimics their natural seasonal cycle in the Mediterranean where winters are mild but temperatures still drop. Place the colony in a cooler location like an unheated room or garage during this period. Do not feed them during diapause but ensure they have access to water. ^[1][4]

Behavior and Temperament

This species is known for its shy, fugitive behavior. Workers are non-aggressive and will typically flee rather than engage in confrontation with threats. They prefer to travel along hidden runways like bark crevices rather than across open surfaces. This makes them somewhat harder to observe than more bold species. They are not known for stinging. Their small size and secretive nature mean they are best suited for keepers who enjoy observing subtle ant behavior rather than dramatic interactions. Colonies tend to grow moderately, not as fast as some tropical species but faster than truly slow-growing ants. ^[2][1]

Colony Founding

Like other Lasius species, Lasius lasioides queens are claustral, the queen seals herself in a chamber and raises the first brood alone, living entirely on her stored fat reserves. She does not leave the nest to forage during founding. After mating, the queen finds a suitable nesting site (under bark, in dead wood, or under a stone), seals herself in, and lays eggs. The first workers (nanitics) will emerge smaller than normal workers and will begin foraging to support the growing colony. This process typically takes 6-10 weeks depending on temperature. Founding colonies should be kept in a quiet, dark location with moderate humidity and warmth. ^[4]

Frequently Asked Questions

References