Chelaner antarcticus

Quick Summary

• Difficulty: Medium
• Origin & Habitat: New Zealand and surrounding islands (Kermadec Islands, Rapa in French Polynesia). Found from subtropical forests in the far north to beech forests and mountain tussock grassland in the south. Nests under half-buried stones or logs in open pastures, grasslands, swamps at high altitudes, forests, and gardens ^[1][2][3].
• Colony Type: Polygynous (multi-queen) colonies are common, one colony was documented with 66 wingless queens, and nine colonies had more than one wingless queen. The species uses ergatoid (wingless) replacement reproductives ^[1].
• Size & Growth:
  • Queen: size data unavailable, related Monomorium species typically range 4-6mm
  • Worker: 2-4mm with substantial variation within colonies ^[1]
  • Colony: Median 1,800 workers, up to approximately 11,400 workers ^[1]
  • Growth: Moderate
  • Development: Estimated 6-10 weeks at optimal temperature based on related Monomorium species (Development timeline not directly studied for this species. Estimates based on genus-level patterns.)
• Antkeeping:
  • Temperature: Keep at 18-24°C. Being from temperate New Zealand, they prefer cooler conditions than tropical ants. Room temperature is likely suitable for most of the year.
  • Humidity: High humidity required, this species actively seeks moist soil and will move colonies to wetter areas. Keep nest substrate consistently moist but not waterlogged. The ideal ratio is approximately 1mL water per 6g soil ^[4].
  • Diapause: Yes, based on New Zealand geographic range, they require a hibernation period. Reduce temperature to 10-15°C for 2-3 months during winter.
  • Nesting: Subterranean nester, they build networks of tunnels and chambers near the soil surface. In captivity, they work well with soil-based formicariums, ant farms, or Y-tong nests with moist substrate. Avoid completely dry conditions.
• Behavior: Aggressive and territorial, they display violent behavior against other ant species and will actively defend their territory. Workers are rarely seen above ground, preferring to forage within soil for seeds and nutrients. They are skilled at suppressing smaller invasive ant colonies. Escape prevention should be good, while small, they are not particularly known for climbing smooth surfaces. However, their small size means standard barriers are still recommended ^[5][4].
• Common Issues: colonies may fail if kept too dry, they actively emigrate from dry conditions and require moist substrate, slow growth compared to tropical ants may frustrate beginners expecting fast development, may be aggressive toward other ant species if housed in shared spaces, the species complex means captive colonies may contain multiple cryptic species, queen loss during founding is common, ensure quiet, dark location with stable conditions

Nest Preferences and Housing

Chelaner antarcticus is a subterranean nester that builds networks of tunnels and chambers 1-3cm below the soil surface. In the wild, they nest under half-buried stones, logs, or directly in soil in various habitats from pastures to forests ^[4]. For captive care, soil-based formicariums or ant farms work best since they allow the ants to exhibit their natural tunneling behavior. Y-tong nests with moist substrate are also suitable. The key requirement is maintaining consistent moisture in the nest material, this species will actively abandon dry areas and move to wetter sections of their enclosure ^[4]. Keep the nest substrate moist but not waterlogged, aiming for roughly 1mL water per 6g of dry substrate. Provide a water reservoir connected to the nest area to maintain humidity over time.

Feeding and Diet

In the wild, these ants forage below ground within soil for seeds and nutrients, though they likely supplement with small insects and honeydew ^[4]. In captivity, offer a varied diet including small protein sources like fruit flies, small crickets, or mealworms. They will also accept sugar sources such as diluted honey or sugar water. Seeds can be offered as enrichment. Feed protein 2-3 times per week and provide constant access to sugar water. Remove uneaten food after 24-48 hours to prevent mold. Their subterranean foraging means they may not readily take food from open foraging areas, place food directly on or in the substrate.

Temperature and Seasonal Care

As a temperate species from New Zealand, C. antarcticus prefers cooler temperatures than many common tropical ant species. Keep the nest area at 18-24°C during the active season. During winter, they require a diapause period, reduce temperatures to 10-15°C for 2-3 months to simulate New Zealand winter conditions. This hibernation period is important for colony health and reproductive cycling. Room temperature is often suitable for this species, but monitor during summer heatwaves as extreme temperatures could be harmful. They are found across New Zealand in areas ranging from very high rainfall (Fiordland: 8000mm) to very low rainfall (Canterbury: less than 500mm), showing adaptability, but consistent moderate conditions are best ^[4].

Colony Structure and Queen Care

This species forms polygynous colonies with multiple queens, one documented colony contained 66 wingless (ergatoid) queens, and nine other colonies had more than one wingless queen ^[1]. This suggests the species naturally maintains multi-queen colonies with wingless replacement reproductives that can take over if the primary queen dies. When keeping this species, you may receive colonies with multiple queens, which is normal for this species. Colony sizes can grow very large, the median is around 1,800 workers but some colonies reach over 11,000 individuals ^[1]. This makes them one of the larger-growing small ant species in New Zealand.

Behavior and Defense

C. antarcticus is notably aggressive compared to many ant species. They display violent behavior toward other ant species and are known to suppress small colonies of the invasive Argentine ant (Linepithema humile) ^[5]. Workers are rarely observed above ground in the wild, suggesting they prefer subterranean foraging and are not highly visible. They are effective competitors and will defend their territory aggressively. Their venom contains unsaturated pyrrolizidines, which may serve as a chemical defense ^[6]. When housing this species, keep them separate from other ant colonies as they may attack and eliminate neighboring ant colonies.

Unique Moisture-Dependent Behavior

This species shows remarkable behavioral responses to soil moisture conditions. Research demonstrated that colonies actively emigrate from dry soil to wetter areas over time, and will move their brood to deeper or wetter chambers during simulated rainfall events ^[4]. Workers grab larvae and toss them down vertical shafts or place them into horizontal tunnels during rainfall, then return them to chambers after rainfall stops. They prioritize moving brood from areas with higher brood density. This behavior means captive colonies are sensitive to drying, always maintain moist substrate. The ideal soil moisture for brood rearing is approximately 1mL water per 6g soil, or 5-10mL per 40g soil ^[4].

Frequently Asked Questions

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References