Lenomyrmex hoelldobleri

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Ecuador (Esmeraldas province), specifically the Alto Tambo area in the Chocó Ecoregion at 676m elevation. This region is part of the Western Cordillera's Evergreen Foothill Forests, characterized by extremely wet conditions with 2000-4000mm annual rainfall ^[1]. The area features secondary forest fragments mixed with pastureland, with temperatures averaging 20-25°C year-round ^[1].
• Colony Type: Unknown, only a single worker specimen has ever been found. Colony structure (single queen vs multiple queens) has not been documented ^[1].
• Size & Growth:
  • Queen: Unknown, no queen specimens have been collected or described ^[1]
  • Worker: 4.77mm total length ^[1]
  • Colony: Unknown, colony size has not been documented ^[1]
  • Growth: Unknown
  • Development: Unknown, no development data exists for this species ^[1] (No captive colonies exist. Development timeline cannot be estimated from related species due to lack of research on Lenomyrmex biology.)
• Antkeeping:
  • Temperature: Based on native habitat: 20-25°C average. However, captive keeping is not recommended, see below. ^[1]
  • Humidity: Native habitat is extremely wet (2000-4000mm rainfall annually). If kept, would require high humidity similar to other Attini species from wet Neotropical forests. ^[1]
  • Diapause: Unknown, no data on seasonal behavior ^[1]
  • Nesting: Unknown, natural nesting behavior has not been documented. The single specimen was found at 676m elevation in foothill forest. ^[1]
• Behavior: Behavior is completely unstudied. As a member of the tribe Attini, they may be ground-foraging and potentially predatory or fungivorous, but this is speculative. Workers possess a functional stinger typical of Myrmicinae ants, though less medically significant to humans than fire ants. Escape risk cannot be assessed without captive observations. ^[1]
• Common Issues: this species is known from a single specimen, there are no captive colonies in existence. keeping this ant would require removing from the wild, which is not recommended for such a rare species., no captive husbandry information exists, any attempt to keep this species would be essentially experimental with no established best practices., distribution is extremely limited, only known from a tiny area in ecuador's chocó ecoregion., the species may have specialized ecological requirements that are not understood, making captive success unlikely., legal considerations: ecuador has biodiversity regulations that may restrict collection and export of native species.

Why This Ant Should Not Be Kept

This is perhaps the most important section: Lenomyrmex hoelldobleri should not be kept in captivity by hobbyists. Here is why:

First, only one specimen has ever been documented, a single worker ant found in 2013 ^[1]. This species was discovered through genetic analysis of a frog's stomach contents, not through field collection of ant colonies. No queen, no brood, no colony has ever been observed by researchers. There are simply no captive colonies in existence anywhere in the world.

Second, the species appears to be extremely rare or localized. The Chocó Ecoregion where it was found is biologically diverse but also highly threatened ^[1]. Removing any individuals from the wild could potentially harm wild populations of a species we barely understand.

Third, even if you could obtain a specimen, there is zero information on how to keep this ant alive. We do not know what they eat, how they nest, what temperature they need, or any basic husbandry requirements. Any attempt to keep them would almost certainly result in death.

Instead of seeking to keep this species, consider supporting ant research or choosing from the many well-documented ant species available in the hobby. ^[1]

Taxonomy and Discovery

Lenomyrmex hoelldobleri was formally described in 2016 by Rabeling, Sosa-Calvo, and colleagues, making it one of the most recently described ant species in the world ^[1]. The species was named to honor Bert Hölldobler, the renowned myrmecologist and co-author of 'The Ants', on the occasion of his 80th birthday ^[1].

The discovery is remarkable because the ant was not collected from the environment but was instead identified from the stomach contents of a Little Devil poison frog (Oophaga sylvatica) ^[1]. This is the first time in history that a new ant species has been described solely from stomach contents, typically, new species are described from specimens collected using standard entomological methods like malaise traps, pitfall traps, or manual collection.

The genus Lenomyrmex contains only a handful of species, and most are known from very few specimens. The genus belongs to the tribe Attini, which includes the famous leaf-cutter ants (Atta and Acromyrmex) that cultivate fungus, though not all Attini are fungus-growers ^[1].

Identification and Morphology

Lenomyrmex hoelldobleri can be identified by several distinctive features. Workers measure approximately 4.77mm in total length, making this the largest known Lenomyrmex species ^[1]. The body is covered with conspicuous costae, ridge-like sculptural elements that create a distinctive textured appearance.

The head, mesosoma, and petiolar region have costae arranged in specific patterns: longitudinal on the head frons, concentric around the eyes, predominantly transverse on the pronotum, and concentrically transverse on the propodeum ^[1]. The propodeum (the section behind the mesosoma) bears two long, acute spines that are longer than the distance between their bases ^[1].

The petiolar node is well-defined and conspicuous, which helps distinguish this species from its closest relative Lenomyrmex costatus ^[1]. The petiole itself is long, fusiform, and pedunculate (having a stalk-like base) ^[1]. Long erect hairs are present on the antennal scapes, and the body is primarily black with lighter legs and coxae ^[1].

Natural History and Habitat

The only known specimen of Lenomyrmex hoelldobleri was collected in Ecuador's Esmeraldas province, specifically 4km southwest of Alto Tambo near the Otokiki Reserve at an elevation of 676 meters ^[1]. This area lies within the Chocó Ecoregion, one of the most biologically diverse regions in the world with exceptionally high levels of endemism ^[1].

The Chocó is also one of the most threatened ecosystems, facing ongoing deforestation from agriculture and logging ^[1]. The region experiences extreme rainfall of 2000-4000mm annually, making it one of the wettest areas in Ecuador ^[1]. Annual temperatures average 20-25°C ^[1].

The habitat where the frog host was collected consisted of secondary forest fragments surrounded by pastureland, part of the Evergreen Foothill Forests of the Western Cordillera ^[1]. These forests are dominated by trees exceeding 30m in height, covered with orchids, bromeliads, ferns, and aroids, with a dense undergrowth of Marantaceae, Araceae, and ferns ^[1]. Two Lenomyrmex species (Lenomyrmex foveolatus and Lenomyrmex hoelldobleri) occur in sympatry in this area ^[1].

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References