Lasius interjectus

Lasius interjectus - "Larger Citronella Ant"

Lasius interjectus is a medium-sized ant native to eastern North America, recognizable by its yellow to brownish-yellow coloration and notably long hairs. Workers measure 3-5mm and have a sharply pointed, notched petiole. When disturbed, they release a distinctive citronella (lemon) scent, a trait shared with other members of the claviger group. Queens are relatively large at 2.35-2.85mm alitrunk length, and colonies can grow substantial in size ^[1][2].

This species is unusual among Lasius ants because it flies in mid- to late spring rather than late summer or autumn. It is also a temporary social parasite, meaning new queens must invade host colonies (typically other Lasius species) to establish their own colonies rather than founding independently. This parasitic lifestyle makes them more challenging to establish in captivity than typical Lasius species ^[3][4].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Eastern North America, ranges from southern New England west to Idaho, south to Wyoming and New Mexico, and east to Oklahoma, Arkansas and Georgia. Found in a wide variety of habitats including woods, grasslands, meadows, and areas near buildings. Nests under stones, logs, in soil, and occasionally creates small mounds ^[2][1].
• Colony Type: Temporary social parasite, single queen colonies (monogyne) that require invasion of host Lasius colonies to establish. Queens kill or coexist with host queens to gain acceptance and use host workers to raise their first brood ^[4][3].
  • Colony: Monogyne
  • Queen: Socially parasitic, Temporary parasitic
• Size & Growth:
  • Queen: 2.35-2.85mm alitrunk length ^[2]
  • Worker: 3.0-5.0mm ^[1]
  • Colony: Colony size can reach several thousand workers based on related species patterns
  • Growth: Moderate, growth depends on successful host colony integration
  • Development: 6-10 weeks (estimated based on related Lasius species) (Development occurs within the host colony using host worker resources. Timeline estimated from typical Lasius patterns since specific data unavailable.)
• Antkeeping:
  • Temperature: Keep at room temperature around 20-24°C. As a temperate species, they do not require extreme heat. A gentle gradient allowing them to choose their preferred temperature works well ^[2].
  • Humidity: Moderate humidity preferred. Keep nest substrate moist but not waterlogged. These ants are subterranean and prefer slightly damp conditions ^[2].
  • Diapause: Yes, requires winter hibernation period. As a temperate species, provide 3-4 months of cold conditions around 5-10°C during winter months ^[2].
  • Nesting: Prefers nesting in soil or under stones. In captivity, a test tube setup works well for founding colonies. Once established, they can be moved to a formicarium with soil or plaster nest chambers. They are subterranean and prefer dark, enclosed spaces ^[2].
• Behavior: Generally docile and non-aggressive. Workers are active primarily underground and are not commonly seen foraging in the open. The citronella scent they release when disturbed serves as their primary defense. Escape risk is moderate, they are not particularly small but can climb smooth surfaces. Use standard barrier methods ^[2].
• Common Issues: establishing colonies is difficult, queens must find and successfully invade host colonies, making wild-caught foundresses more reliable than captive-bred, host colony requirement means you need appropriate host species (Lasius claviger, L. latipes, or similar) for successful colony founding, colonies may fail if the host colony is too small or unhealthy to support the parasitic queen and her brood, they are attracted to lights which can cause disorientation in captivity, keep their housing away from bright lights, subterranean lifestyle means you may not see much activity in the outworld

Colony Founding and Parasitism

Lasius interjectus is a temporary social parasite, which means new queens cannot found colonies independently like most ants. Instead, after mating, a queen must find an established colony of a host Lasius species (commonly Lasius claviger, L. latipes, or related species) and invade it. The host colony tends to accept the intruding queen relatively readily. Once inside, the parasitic queen may kill the host queen or coexist with her, using the host workers to raise her own brood ^[4]. This parasitic founding strategy makes captive establishment challenging, you will need either a wild-caught queen that has already invaded a host colony, or you must provide a host colony for a newly caught queen to invade. The host colony must be healthy and substantial enough to support both the parasitic queen and the existing colony ^[3].

Housing and Nest Setup

For initial housing, use a standard test tube setup with a water reservoir. Since these ants are subterranean, they prefer dark, enclosed spaces. Once the colony is established and growing, you can transfer them to a formicarium with soil-based or plaster nest chambers. Keep the nest area humid but not wet, the substrate should feel damp but not soggy. These ants do not need much vertical space in the outworld since they spend most of their time underground. Provide a shallow foraging area with sugar water and protein sources. Keep the setup away from direct sunlight and vibrations, as these ants prefer stable, dark conditions ^[2].

Feeding and Diet

Like other Lasius species, Lasius interjectus workers feed on honeydew (the sugary liquid excreted by aphids) and will readily accept sugar water or honey. They also need protein sources for brood development, offer small insects like fruit flies, small crickets, or mealworms. In the wild, they are generalist feeders with a preference for honeydew, but they will scavenge protein from various sources. Feed sugar water constantly (on a cotton ball or in a feeder) and offer protein prey 2-3 times per week. Remove uneaten prey after 24 hours to prevent mold ^[2].

Seasonal Care and Hibernation

As a temperate species, Lasius interjectus requires a winter hibernation period. Reduce temperatures to around 5-10°C for 3-4 months, typically from late October through early March. During this time, colony activity slows significantly. You can move the colony to an unheated garage, basement, or refrigerator (not freezer) for this period. Do not feed during hibernation, but ensure the water tube has enough water to last the entire period. Return to room temperature gradually in spring. This species is unusual in that it can have nuptial flights during winter when colonies are near heated buildings, but for captive colonies, follow the natural temperate cycle with proper hibernation ^[2].

Behavior and Defense

Lasius interjectus is generally docile and not aggressive toward keepers. Their primary defense mechanism is the citronella (lemon) scent they release when disturbed or crushed, this is a characteristic shared with all species in the claviger group. Workers are primarily subterranean and spend most of their time underground, so you may not see much activity in the outworld. They are not particularly aggressive and rarely bite or sting. Their attraction to lights is notable, in the wild, this species is more frequently caught at lights than other Lasius species, which can cause confusion during nuptial flight season ^[2].

Frequently Asked Questions

References