Lasius excavatus

Quick Summary

• Difficulty: Unknown, newly described species with extremely limited data
• Origin & Habitat: Southern Iran highland desert at 2200-2500m elevation, found in light Quercus woodland and tree stands in ancient Maymand settlement ^[1]
• Colony Type: Unconfirmed, likely single-queen colonies based on typical Lasius patterns
• Size & Growth:
  • Queen: Estimated 7-9mm, inferred from Lasius genus patterns
  • Worker: Approximately 3mm, inferred from Lasius genus ^[1]
  • Colony: Unknown, no published colony data available
  • Growth: Unknown
  • Development: Estimated 6-10 weeks based on typical Lasius development (Development timeline not directly studied, estimate based on genus patterns)
• Antkeeping:
  • Temperature: Keep at 22-26°C with a gentle gradient. Based on Iranian highland origin, they likely tolerate warmer conditions than typical European Lasius but avoid extreme heat.
  • Humidity: Prefer drier conditions, mimic arid highland environment. Keep substrate moderately dry with a small moist area. Avoid constant saturation.
  • Diapause: Likely requires winter rest period of 2-3 months at 5-10°C based on high-altitude Iranian origin. Unconfirmed.
  • Nesting: Arboricolous in nature, likely prefer elevated nest sites. Y-tong nests work well. Provide climbing structures.
• Behavior: Temperament is typical of small Lasius, generally non-aggressive but may be timid. Foraging style is typical of Lasius, likely collecting honeydew and small prey. Escape risk is moderate due to small size, use standard barriers but fine mesh is advisable. Not known to sting.
• Common Issues: newly described species with no captive breeding data, expect a learning curve, extreme rarity makes finding colonies difficult, specific humidity requirements unclear, start dry and adjust based on colony behavior, winter care requirements unconfirmed, monitor for dormancy signals, limited information on acceptable foods, begin with standard Lasius diet

Discovery and Taxonomy

Lasius excavatus was formally described in 2020 by Bernhard Seifert, making it one of the newest recognized ant species in the Palaearctic region. It belongs to the Lasius brunneus species complex within the niger clade of the subgenus Lasius s.str. The species name 'excavatus' refers to the distinctive excavation observed on the posterior margin of the head. This feature, combined with longer scapes, a lower number of mandibular teeth (7), and very smooth body surface texture, distinguishes it from its closest relatives including Lasius brunneus, Lasius silvaticus, and Lasius himalayanus ^[1]. The species is considered probably endemic to Iran, meaning it is likely found only there.

Natural Habitat and Distribution

This species has an extremely limited distribution known only from two locations in the highland desert of southern Iran. The first locality is near Shar-e-babak in the Maymand area at 2220m elevation, where it was found in a garden setting among trees. The second locality is near Sisakht in the Kharidun area at 2500m elevation, in an oak steppe forest, also found on trees ^[1]. The climate in these areas is harsh, summers are very hot, winters are extremely cold, and aridity is high throughout the year. The ants are found only in rare spots where trees provide less extreme conditions, specifically in light Quercus woodland and tree stands in the ancient Maymand settlement. Being arboricolous is unusual for Lasius, as most species nest in soil or under stones.

Housing and Nest Preferences

Based on the species' arboricolous nature, captive colonies will likely do best with elevated nest options. Y-tong nests work well for small Lasius species, or you could provide a naturalistic setup with cork or wooden structures that allow the ants to climb. The key is providing a dry to moderately humid environment rather than the damp conditions preferred by many other ants. Because they come from an arid highland climate, avoid overly moist substrates. A small water tube for humidity is sufficient, watch that condensation does not make the nest too wet. Escape prevention should be moderate, while not as tiny as some species, they can still squeeze through small gaps, so standard barriers are advisable.

Feeding and Diet

Like other Lasius species, these ants likely have a mixed diet. They probably tend aphids for honeydew in captivity, which should be your primary sugar source, offer sugar water or honey regularly. For protein, small live prey such as fruit flies, small mealworms, or other tiny insects will likely be accepted. Start with standard Lasius foods and observe what your colony prefers. Given their origin in a harsh environment with limited resources, they may be opportunistic feeders. Avoid large prey items, their workers are small so prey should be appropriately sized.

Temperature and Seasonal Care

Based on their Iranian highland origin, Lasius excavatus likely tolerates a wider temperature range than typical European Lasius. Start around 22-26°C for optimal colony activity and brood development. They probably handle warmer temperatures better than most Lasius due to their hot native habitat. However, avoid placing them in direct heat or temperatures exceeding 30°C. For winter, based on the cold winters at 2500m elevation, they likely need a diapause period. Provide 2-3 months at 5-10°C during winter, mimicking the cold season they experience in their natural habitat. Monitor your colony for signs of slowing activity in autumn as a cue to begin cooling.

Frequently Asked Questions

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References