Dorymyrmex tener

Dorymyrmex tener

Dorymyrmex tener is a small to medium-sized ant native to Chile and Argentina, belonging to the Dolichoderinae subfamily. Workers are characterized by a distinctive psammophore, a basket-like arrangement of hairs on the underside of the head used for carrying sand ^[1]. They are found throughout the Patagonian region, from central Chile east to Argentina. This species is one of the most abundant and aggressive ant species in its range, known for its opportunistic feeding habits and aggressive defense of aphids ^[2]. They inhabit open areas and can be found nesting under rocks, making them a common sight in Patagonian steppe environments.

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Native to Chile and Argentina, specifically the Patagonian region from Argentina (Neuquén to Chubut provinces) across to Chile. They inhabit open areas, steppe environments, and typically nest under rocks or in soil ^[3][1].
• Colony Type: Colony structure is unconfirmed from available research. Based on typical Dolichoderinae patterns, likely single-queen colonies.
• Size & Growth:
  • Queen: Estimated 6-8mm based on genus patterns
  • Worker: Estimated 3-5mm based on genus patterns
  • Colony: Likely moderate colonies based on their abundance and dominance in the region
  • Growth: Moderate, based on typical Patagonian ant development patterns
  • Development: Estimated 8-12 weeks at optimal temperature based on similar Patagonian Dolichoderinae (Development time is estimated based on related species, specific timeline unconfirmed for this species)
• Antkeeping:
  • Temperature: Keep at room temperature around 18-24°C. As a Patagonian species, they prefer cooler conditions than tropical ants. Provide a temperature gradient allowing workers to choose their preferred zone ^[3].
  • Humidity: Low to moderate humidity, these ants naturally inhabit dry to semi-dry open areas and steppe environments. Allow the nest substrate to dry partially between waterings.
  • Diapause: Yes, as a Patagonian species from southern South America, they require a winter rest period. Reduce temperature to around 10-15°C for 3-4 months during winter.
  • Nesting: Provide a naturalistic setup with a dry to semi-dry substrate. They naturally nest under stones and in soil, so a Y-tong or plaster nest with some moisture but not wet conditions works well. Avoid overly humid setups.
• Behavior: Dorymyrmex tener is an aggressive, opportunistic forager that actively defends resources. They are known for their aggressive aphid-tending behavior, they patrol thistles and protect aphids from predators, effectively expelling other insects from plants ^[2]. Workers are active foragers that will collect honeydew, small insects, and other protein sources. They are not particularly large ants but can deliver a noticeable bite if handled. Escape risk is moderate, use standard barrier methods but they are not known escape artists.
• Common Issues: Patagonian origin means they need proper hibernation, colonies that are kept warm year-round may decline, They prefer drier conditions than many ants, overhumid setups can cause stress and mold issues, Wild-caught colonies may carry parasites that affect captive survival, Their aggressive defense of aphids means they may attack and kill other insects in the outworld, As ground-nesting ants, they need proper depth in the nest for tunneling behavior

Natural History and Distribution

Dorymyrmex tener is native to the southern cone of South America, specifically Chile and Argentina. They are found throughout the Patagonian region, from central Argentina (Neuquén Province at approximately 38°S) south to Chubut Province (approximately 42.5°S) ^[3]. The species has been recorded at various elevations, including high-altitude areas in Mendoza (2000-3000m) ^[4]. They are one of the most ubiquitous and numerically dominant ant species in their range, frequently encountered in roadside steppe and open areas ^[2]. The species belongs to the D. tener species group and was formerly classified under the genus Araucomyrmex before being reclassified back to Dorymyrmex ^[1].

Feeding and Diet

Dorymyrmex tener is an opportunistic generalist with a varied diet. In the wild, they primarily feed on honeydew from aphids, particularly the species Brachycaudus cardui found on thistles ^[5][6]. They actively tend these aphids, collecting the sugary honeydew in exchange for protecting the aphids from predators and parasitoids ^[2]. Beyond honeydew, they are generalist predators that consume various insects, spiders, and other small arthropods ^[3][2]. In captivity, offer a varied diet including sugar water or honey as a honeydew substitute, small live or frozen insects (fruit flies, small crickets, mealworms), and occasionally other protein sources. Their aggressive nature means they will readily take protein baits and defend food resources.

Temperature and Seasonal Care

As a Patagonian species from southern South America, Dorymyrmex tener is adapted to cooler temperatures than many ant species. Keep the nest area at room temperature, ideally around 18-24°C, with some variation allowed ^[3]. They are active in open areas and can tolerate temperature fluctuations. During the winter months (roughly May-August in the southern hemisphere), the colony should be allowed to rest at reduced temperatures of around 10-15°C for approximately 3-4 months. This mimics their natural seasonal cycle in the Patagonian region. Do not keep them warm year-round as this can stress the colony and shorten its lifespan. A temperature gradient allows workers to self-regulate their body temperature.

Nesting and Habitat

In the wild, Dorymyrmex tener nests in soil, typically under rocks or in open ground areas ^[3]. They are described as epigeic (ground-nesting) ants that live and forage in open areas. Workers have a psammophore, a specialized structure of hairs on the underside of the head used for carrying sand and excavating nests ^[1]. For captive care, provide a naturalistic setup with a dry to semi-dry substrate, or a Y-tong/plaster nest that doesn't retain excessive moisture. They prefer conditions that are drier than many tropical ant species. A layer of sand or soil in the outworld allows for natural foraging behavior. Avoid overly humid or wet setups.

Behavior and Colony Dynamics

This species is known for its aggressive and active foraging behavior. Dorymyrmex tener is one of the most aggressive aphid-tending ant species in its range, effectively defending aphids from predators and expelling other insects from plants ^[2]. They show a strong preference for high-quality honeydew sources and will actively patrol aphid-infested plants. Colonies maintain multiple entrance points and can be quite active in the outworld. Workers are opportunistic and will investigate and defend food resources vigorously. The colony will likely grow to a moderate size over several years. Queens are not as robust as some species but are capable of establishing colonies successfully in appropriate conditions.

Frequently Asked Questions

References