Lasius coloradensis

Lasius coloradensis - "Colorado Citronella Ant"

Lasius coloradensis is a small to medium-sized ant native to western North America, ranging from New Mexico and Colorado north to Manitoba and Alberta. Workers are yellowish brown to brown with a distinctive petiole that has a sharp apex when viewed from the side and typically shows a notch when viewed from the front. They nest under stones in rocky or sandy soils, commonly found in prairies, deciduous forests, ponderosa pine habitats, and coniferous forests across elevations from below 2000 to over 7000 feet. This species is closely related to Lasius claviger but averages smaller in size. A notable aspect of this species is that it is likely a temporary social parasite, the queen invades another ant colony, kills the host queen, and uses the host workers to raise her first brood before her own workers take over.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Western North America, from New Mexico, Colorado, and Utah north to Manitoba and west to Alberta and Oregon. Found in prairies, deciduous forests, ponderosa pine-gamble oak transition zones, and coniferous forests. Nests under stones in rocky or sandy soils on dry grassy slopes ^[1].
• Colony Type: Likely temporary social parasite, queen invades host colony, kills host queen, and uses host workers temporarily. Single-queen colonies in founding stage. Colony structure unconfirmed for established colonies.
  • Colony: Monogyne
  • Queen: Temporary parasitic
• Size & Growth:
  • Queen: Approximately 6-7mm based on genus typical size (estimated)
  • Worker: Approximately 3-5mm based on description as smaller than L. claviger (estimated)
  • Colony: Unknown for this specific species, likely several hundred workers based on related Lasius species (estimated)
  • Growth: Moderate, estimated based on related species patterns
  • Development: 6-10 weeks based on typical Lasius development at optimal temperature (estimated) (Development time estimated from related Lasius species, actual timeline unconfirmed for this species)
• Antkeeping:
  • Temperature: Keep at room temperature around 20-24°C. They naturally occur in temperate to cool climates so they do not require high heat. A slight temperature gradient allows workers to regulate their conditions.
  • Humidity: Moderate humidity, they nest under stones in soils that range from dry to slightly moist. Keep nest substrate moderately moist but allow some drying between waterings. Avoid waterlogging.
  • Diapause: Yes, as a temperate species, they require a winter rest period. Reduce temperature to around 5-10°C for 2-3 months during winter months (roughly November-February depending on your location).
  • Nesting: Y-tong (acrylic) nests or test tube setups work well. They prefer nesting in dark, confined spaces. A naturalistic setup with stones over moist substrate can also work. Keep the nest in moderate humidity with some dry areas available.
• Behavior: Workers are relatively docile and not aggressive. They are moderate foragers, typical of Lasius species. Escape risk is moderate, use standard barrier methods. They likely tend aphids for honeydew like other Lasius species. Queens are temporary social parasites so founding behavior involves finding a host colony.
• Common Issues: temporary parasitic founding means finding a host colony can be challenging for captive breeding, colonies may fail if proper host species is not available during queen founding, winter diapause is required, failing to provide this can weaken or kill colonies, wild-caught colonies may have parasites that affect captive survival, small colony size means they are sensitive to disturbance

Species Identification and Range

Lasius coloradensis is a North American ant species that was once considered a subspecies of Lasius claviger before being raised to full species status. Workers are distinguished by their petiole having a sharp apex when viewed from the side and a distinct notch when viewed from front. Their body color ranges from yellowish brown to brown, typically darker than related species. The hairs on the underside of their head are usually less than 0.20mm in length and cover only the posterior portion. This species ranges from New Mexico, Colorado, and Utah north to Manitoba and west to Alberta and Oregon, making it primarily a western North American species. ^[1]

Natural Habitat and Nesting

In the wild, Lasius coloradensis nests under stones in rocky or sandy soils. Studies show that most nests are found under stones, with some under cow dung. They prefer dry grassy slopes with scattered tree cover, and they occur across a wide elevation range from below 2000 feet to over 7000 feet. Their habitat includes prairies, deciduous forests, ponderosa pine communities, and coniferous forests. This preference for nesting under stones means they naturally inhabit areas where ground cover provides shelter while allowing some sunlight exposure to warm the stones. ^[1]

Temporary Parasitism and Reproduction

This species is likely a temporary social parasite, meaning the founding queen must invade a host ant colony (likely another Lasius species such as Lasius neoniger). She kills the host queen and uses the host workers to raise her first brood until her own workers emerge. This parasitic founding method is challenging for captive propagation since finding an appropriate host colony is difficult. Nuptial flights occur from late July through mid-September, with one sample from September 16 containing both alates and dealate queens but no workers, suggesting late-season mating flights. One sample collected December 27 contained only dealate queens. ^[1]

Temperature and Seasonal Care

As a temperate species from higher elevations, Lasius coloradensis requires a winter diapause period. During active season, keep them at typical room temperature around 20-24°C. They do not require heated setups since their natural range includes cool mountainous regions. In winter, reduce temperatures to approximately 5-10°C for 2-3 months, mimicking natural winter conditions. This diapause period is essential for colony health and reproduction. Failure to provide proper hibernation can weaken colonies and prevent reproduction. ^[1]

Feeding and Diet

Like other Lasius species, Lasius coloradensis likely feeds on honeydew from aphids and scale insects, plus protein from small insects. In captivity, offer sugar water or honey water as a constant energy source, along with small insects like fruit flies, pinhead crickets, or mealworms. They are not aggressive predators but will collect protein from dead insects. Feed protein sources 2-3 times per week and provide sugar water continuously. Remove uneaten food promptly to prevent mold. ^[1]

Housing and Nest Setup

Y-tong (acrylic) nests work well for this species, providing dark, enclosed chambers that mimic their natural stone-cover nesting preference. Test tube setups are also suitable for founding colonies. Use moderate humidity in the nest, they naturally nest in soils that can dry out between rains. A naturalistic setup with flat stones placed over moist soil can replicate their wild habitat. Provide a foraging area with access to sugar water and protein sources. Standard escape prevention methods are adequate for their medium size. ^[1]

Frequently Asked Questions

References