Forelius antarcticus

Forelius antarcticus

Forelius antarcticus is a small, dark brown ant native to Chile, recently transferred from the genus Tapinoma to Forelius ^[1]. Workers measure about 2mm in length and are a uniform brown color, making them very similar in appearance to the invasive Argentine ant but darker ^[2]. Queens are larger at around 4mm with relatively long antennae and shorter mesosomas compared to related species ^[1]. This ant is endemic to Chile, found from Antofagasta in the north down to Linares in the south ^[2][3]. In their natural habitat, these ants build shallow nests under stones in dry to semi-desert areas, including the edge of the Atacama Desert ^[4][1]. They are seed collectors and show some behavioral adaptations for water carrying, though not as extreme as honey pot ants ^[4].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Endemic to Chile, found from Antofagasta to Linares in dry to semi-desert habitats, often nesting under stones in coastal matorral ^[4][2][1].
• Colony Type: Single-queen colonies (monogyne), typical for Dolichoderinae, though not directly studied for this species
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: 3.5-4mm total (HL 0.83-0.85mm, WL 1.59-1.63mm) ^[1]
  • Worker: 1.8-2mm (HL 0.57-0.61mm, WL 0.61-0.65mm) ^[5][1]
  • Colony: Unknown for this species, likely moderate, typical for desert-dwelling Dolichoderines
  • Growth: Moderate, inferred from similar Chilean ants
  • Development: 6-10 weeks (estimated based on typical Dolichoderine development at room temperature) (Development time not directly studied, estimates based on related Forelius species and Chilean climate conditions)
• Antkeeping:
  • Temperature: Room temperature (18-24°C) is suitable. They tolerate dry, warm conditions well given their desert origin. A gradient of 20-26°C works well ^[1].
  • Humidity: Low to moderate, prefer dry conditions typical of their semi-desert habitat. Keep nest substrate slightly moist but allow drying periods. Avoid overly humid conditions.
  • Diapause: Unknown, Chile has mild winters in the northern parts of their range. A brief cool period (2-3 months at 10-15°C) may benefit colonies, but is not required.
  • Nesting: Shallow nests under stones in nature, test tubes or Y-tong nests work well. Provide a dry to slightly moist substrate. They do well in formicariums with compact chambers.
• Behavior: These are active foragers that collect seeds and tend honeydew-producing insects. They are not aggressive and typically avoid confrontation. Workers are small but fast-moving. Escape prevention should be moderate, their small size means they can fit through small gaps, but they are not strong climbers like some Dolichoderines. They are daytime foragers, active when surface soil temperatures are suitable ^[6].
• Common Issues: small size means escapes are possible without proper barriers, dry habitat preferences mean overwatering can cause fungal problems, wild-caught colonies may have parasites specific to Chilean ants, limited availability makes this a specialty species for collectors

Housing and Nest Setup

Forelius antarcticus does well in standard ant housing setups. Test tubes work perfectly for founding colonies, use a water reservoir at one end with a cotton plug creating a humid chamber, while the other end remains dry for the queen to seal herself in. Once the colony reaches 20-30 workers, you can move them to a formicarium. Y-tong (AAC) nests or plaster nests work well because they allow you to control humidity precisely. Given their preference for dry conditions, keep the nest relatively dry with only a small water chamber. Avoid naturalistic setups with soil unless you have experience, these ants prefer compact chambers over elaborate tunnels. Escape prevention should be moderate: use Fluon on the rim of formicariums and ensure any connections are tight, as workers at 2mm can squeeze through small gaps. ^[4][1]

Feeding and Diet

In the wild, these ants collect grass seeds and tend honeydew-producing insects ^[4]. In captivity, offer a varied diet: sugar water or honey as an energy source (always available), protein sources like small crickets, mealworms, or fruit flies, and seeds or grain as a natural food item. They are not aggressive predators, so prey items should be small and easy to handle. Feed protein 2-3 times per week, and keep sugar water constantly available once workers emerge. Remove uneaten food after 24-48 hours to prevent mold. Given their desert origin, they may be more tolerant of dry food, seeds can be left longer than perishable protein.

Temperature and Seasonal Care

These ants come from a wide range of Chilean latitudes (Antofagasta to Linares), so they adapt well to typical room temperatures. Keep them between 20-26°C for optimal activity and brood development. They tolerate warmer conditions well given their semi-desert origin. During the summer months (roughly November to March in the southern hemisphere), they will be most active. In winter, you can reduce temperatures slightly to simulate seasonal changes, but a full hibernation is not required given Chile's relatively mild winters. A brief cool period at 15-18°C for 2-3 months may help synchronize their biology but is not strictly necessary. Avoid temperatures below 10°C for extended periods. ^[2][1]

Behavior and Colony Dynamics

Forelius antarcticus is a daytime-active species whose foraging patterns are influenced by surface soil temperature ^[6]. Workers are fast-moving and efficient foragers, characteristic of desert ants. They are not particularly aggressive and will typically flee rather than engage in confrontation. The colony will establish a single queen (monogyne) that seals herself in during founding. The first workers (nanitics) will be smaller than normal workers and will immediately begin foraging to support colony growth. Colonies grow moderately, expect 6-12 months from founding to a stable colony of 50+ workers. They are not known for being escape artists in the sense of climbing smooth surfaces, but their small size means they can fit through tiny gaps in setup connections.

Field Collection and Acquisition

This is an endemic Chilean species that is rarely available in the antkeeping hobby outside of Chile ^[3]. If you are in Chile and wish to collect a colony, look for shallow nests under stones in dry, semi-desert areas, particularly in the central and northern regions where the species is most common. Collect a queen along with at least 10-15 workers to ensure the colony has enough workers to sustain itself during the founding period. Use a shovel or trowel to carefully excavate under stones. Outside of Chile, this species is very difficult to obtain and is not commonly traded. If you encounter one for sale, ensure it was legally collected and that shipping to your country is permitted.

Frequently Asked Questions

References