Strumigenys collinsae

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Colorado, USA (Pueblo County,23 miles north of Walsenburg) at 1802m elevation. The label indicates oak woodland, though the collector only reported sampling yellow pine and juniper litter ^[1]. Strumigenys species typically inhabit leaf litter and rotting wood in forested areas.
• Colony Type: Unknown, only a single queen has ever been collected. Based on genus patterns, likely single-queen (monogyne) colonies with claustral founding.
• Size & Growth:
  • Queen: Size data unavailable, inferred from Strumigenys genus (~3mm total length)
  • Worker: Size data unavailable, inferred from Strumigenys genus (~2-3mm total length)
  • Colony: Unknown, no colony data exists
  • Growth: Unknown, likely slow based on genus patterns
  • Development: Unknown, likely 8-12 weeks based on related Strumigenys species (No direct data exists. Development times inferred from genus-level studies on similar litter-dwelling ants.)
• Antkeeping:
  • Temperature: Unknown for this species. Keep at room temperature (20-24°C) as a starting point and observe colony activity. Related Strumigenys species prefer stable, moderate temperatures.
  • Humidity: High humidity required, these are leaf litter ants that need damp substrate conditions. Keep the nest substrate consistently moist but not waterlogged. Given the dry Colorado habitat, provide a moisture gradient to allow the ants to choose their preferred level.
  • Diapause: Unknown, likely requires a winter rest period given the Colorado origin (temperate climate). Related temperate Strumigenys species typically undergo diapause.
  • Nesting: No specific data. In captivity, Strumigenys do well in small test tube setups or naturalistic setups with damp leaf litter. Tight chambers scaled to their tiny size work best.
• Behavior: No behavioral observations exist for this species. Based on genus patterns, they are specialized predators of springtails and other micro-arthropods, using their trap-jaw mandibles to capture prey. They are likely shy and non-aggressive, preferring to avoid confrontation. Their tiny size means excellent escape prevention is critical, they can squeeze through remarkably small gaps.
• Common Issues: extreme rarity makes this species essentially unavailable to keepers, only known from a single specimen collected in 1958, no captive breeding history exists, this species has never been kept in captivity, escape prevention is critical due to their tiny size, use fine mesh and tight-fitting lids, specialized predator diet may be difficult to provide, they require live micro-prey like springtails, virtually no information on colony founding, development, or care requirements

Species Discovery and Rarity

Strumigenys collinsae was only recently recognized as a distinct species, it was formally described in 2021 by Douglas Booher ^[1]. Before that, the single known specimen had been sitting in a museum collection misidentified as Strumigenys pilinasis (a junior synonym of Strumigenys pilinasis) since 1958. The queen was collected by Clayton Hoff on August 15,1958,from sifted leaf litter in Pueblo County, Colorado, at an elevation of 1802 meters. This remains the only known specimen of the species, no workers, males, or wild colonies have ever been documented. The species name 'collinsae' honors the collector's wife, Dorothy Collins, whose assistance was acknowledged in the original collection notes ^[1].

Identification and Morphology

This species is distinguished from all other North American Strumigenys by its unique dental arrangement, four principal teeth with the first two nearly equal in size, followed by two smaller teeth of equal size ^[1]. The mandibles have a distinctive basalmost tooth following a large diastemmic gap that does not overlap when the mandible is closed and is less than half the length of the following tooth. The setae on the margins and dorsum of the clypeus are fine and often curve strongly along the apical portion, barely extending past the margin. It is most similar to Strumigenys reliquia, sharing similar clypeus shape, mandible dentition, and pilosity, but differs in that S. reliquia has a much shorter second principal tooth and possesses flagellate apicoscrobal and tibial setae that S. collinsae lacks ^[1]. Exact body measurements are unavailable as only head and other part measurements were recorded, but the species is very small.

Habitat and Distribution

Strumigenys collinsae is known only from a single location in Colorado, approximately 23 miles north of Walsenburg in Pueblo County ^[1]. The elevation of 1802 meters (about 5900 feet) indicates a cool, montane environment. The specimen label originally indicated oak woodland habitat, but this appears to be a mislabeling, the collector Clayton Hoff only reported sampling yellow pine and juniper litter in his published work on pseudoscorpions. This discrepancy is significant because it suggests the actual habitat preference may be different from what was originally recorded. Strumigenys species typically inhabit moist leaf litter and rotting wood in forested environments, so the pine-juniper sampling data may be more accurate than the oak woodland label ^[1].

Care Recommendations (Inferred from Genus)

Since no captive care history exists for this species, all recommendations must be inferred from what is known about Strumigenys genus biology. These are specialized predators that primarily hunt springtails and other tiny arthropods in leaf litter. In captivity, you would need to provide a constant supply of live micro-prey, springtails are the ideal staple food. They require high humidity and should be kept in small, tight chambers scaled to their tiny size. The queen likely seals herself in during founding (claustral founding), living off stored fat reserves until her first workers emerge. Temperature should be moderate, around 20-24°C, given the temperate Colorado origin. A winter diapause period is likely needed, though specific requirements are unknown. Escape prevention is absolutely critical due to their minute size ^[2].

Why This Species Is Not Available to Keepers

It is important to understand that Strumigenys collinsae is essentially unavailable to the ant-keeping hobby. This species is known from a single queen collected over 65 years ago, no additional specimens have ever been found despite extensive ant surveys in the western United States. There are no breeding colonies in captivity because the species has never been collected alive. Even if additional wild colonies were discovered today, the specialized care requirements and extreme rarity would make this an expert-only species. For keepers interested in Strumigenys, more common North American species like Strumigenys pilinasis or Strumigenys mississippiensis are far more practical choices, as they have established care histories and are occasionally available from suppliers.

Frequently Asked Questions

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References