Stegomyrmex bensoni

Stegomyrmex bensoni

Stegomyrmex bensoni is an extremely rare Neotropical ant species known from a single specimen collected in the Amazon region of Brazil. Workers are small but robust at about 6.4mm total length, with a distinctive reddish-brown coloration and remarkably hairy bodies covered in golden, multibranched (plumose) hairs that give them a fuzzy appearance ^[1]. The genus Stegomyrmex belongs to the tribe Solenopsidini, which includes well-known ants like fire ants (Solenopsis). This species was discovered in a cave near Serra dos Carajás in Pará, Brazil, representing the first record of this ant group in the entire Amazon region ^[1][2].

What makes S. bensoni particularly special is how little we know about it. Only ONE worker has ever been documented, meaning there is no information about queens, males, colony structure, or behavior in captivity. The single known specimen was found near the entrance of a cave (Gruta NV06), but researchers note there's no proof this species is restricted to caves ^[1]. This is truly a mystery ant, keeping it would be an adventure into the unknown.

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Serra dos Carajás, Pará, Brazil (Amazon region). The single known specimen was collected near the entrance of a cave (Gruta NV06), but whether this represents their true habitat or just where one individual happened to be found is unknown ^[1][2].
• Colony Type: Unknown, only a single worker has ever been documented. Colony structure (single-queen vs multi-queen) is completely unconfirmed.
• Size & Growth:
  • Queen: Unknown, no queens have ever been described for this species ^[1].
  • Worker: 6.4mm total length (TL), with head width (HW) of 1.26mm ^[1].
  • Colony: Unknown, only one worker has ever been found ^[1].
  • Growth: Unknown, no colony development has ever been observed.
  • Development: Unknown, no breeding or development data exists for this species. (No data exists on egg-to-worker development. Based on typical Solenopsidini patterns, expect several weeks to a few months at warm temperatures, but this is purely speculative.)
• Antkeeping:
  • Temperature: Unclear, no thermal data exists for this species. The Amazon region stays warm year-round, so aim for 24-28°C as a starting point and observe colony activity. A gentle heat gradient allows the ants to choose their preferred temperature.
  • Humidity: High humidity is likely needed, matching the humid Amazon forest environment. Keep the nest substrate consistently moist but not waterlogged. The cave collection site suggests they tolerate damp conditions.
  • Diapause: Unknown, Amazon ants typically don't enter true hibernation, but seasonal activity changes are possible. No data exists.
  • Nesting: Unknown, no natural nesting observations exist. The cave specimen suggests they might tolerate dark, humid environments. A naturalistic setup with moist substrate or a Y-tong/plaster nest would be reasonable starting points. Avoid overly dry conditions.
• Behavior: Completely unknown. Based on tribe membership (Solenopsidini), they are likely predatory or omnivorous, potentially hunting small invertebrates. Escape risk cannot be assessed since we've never kept them, but at 6.4mm they are not tiny and standard barriers should work. Temperament is unconfirmed, some Solenopsidini are aggressive while others are more docile.
• Common Issues: this species has never been kept in captivity, there is no established care protocol, only one wild specimen has ever been found, making acquisition extremely unlikely, no information exists on what they eat or how they forage, colony founding behavior is completely unknown, we don't know if queens are claustral, no data on temperature or humidity preferences specific to this species, obtaining legal specimens would be extremely difficult as they are not in the hobby

Rarity and Collection History

Stegomyrmex bensoni is one of the rarest ants in the world in terms of documented specimens. The entire scientific knowledge of this species comes from a single worker collected in February 2008 by arachnologist Renata Andrade while studying cavernicolous pseudoscorpions in Serra dos Carajás, Pará, Brazil ^[1]. The specimen was found near the entrance of cave NV06,which is why researchers initially thought they might be cave-dwelling. However, since only one individual has ever been found, we cannot say with certainty whether caves are their true habitat or just where one forager happened to be wandering ^[1]. This species represents the first record of the entire subfamily Stegomyrmecini in the Amazon region, showing how little we know about ant diversity in tropical South America.

Identification and Appearance

This species can be identified by several distinctive features. The most striking is the multibranched (plumose) golden hairs covering much of the body, these branched hairs are especially dense on the head corners, the underside of the waist segments, and the front of the gaster ^[1]. The metapropodeal groove (the indentation between the middle body and the rear body) is deeply impressed, and the petiole lacks the small spines underneath that some related species have. Workers measure about 6.4mm total length with a reddish-brown color ^[1]. The eyes are exceedingly small with only about three almost indistinct facets, suggesting they may not rely heavily on vision. The propodeal spines are short and triangular, almost hidden by the dense pilosity.

Housing and Nesting (Speculative)

Since no one has ever kept this species in captivity, all housing recommendations are educated guesses based on related ants in the Solenopsidini tribe and the Amazon collection environment. A naturalistic setup with moist substrate would be a reasonable starting point, think damp forest floor conditions. A Y-tong (AAC) nest or plaster nest with good humidity retention would also be appropriate. Given the cave collection, they may tolerate or even prefer darker nest conditions. Provide a water tube and keep the nest area consistently moist. Since we don't know their exact preferences, observe how the ants position themselves, if they cluster in humid areas, increase moisture, if they avoid condensation, reduce it. A small outworld for foraging allows you to offer food and observe their hunting behavior.

Feeding and Diet (Speculative)

The Solenopsidini tribe includes both predatory ants and those that tend aphids for honeydew. Without any direct observation of feeding behavior, we must speculate based on related species. Start with small live prey like fruit flies, pinhead crickets, or small mealworms, these are accepted by most Solenopsidini. You might also offer a sugar source like honey or sugar water, though some tribe members are primarily predatory. Since this is an Amazon species, they likely forage actively and may accept a variety of foods. The tiny eyes suggest they may hunt by chemical cues rather than vision. Offer a varied diet and note what gets consumed. Remove uneaten prey after 24-48 hours to prevent mold.

Temperature and Seasonal Care

No specific temperature data exists for S. bensoni, but the Amazon environment provides clues. The Serra dos Carajás region stays warm year-round with average temperatures in the mid-to-high 20s Celsius. Start with a range of 24-28°C and monitor colony activity, if workers become sluggish, slightly increase heat, if they avoid the heated area, reduce it. A heating cable on one side of the nest creates a gradient allowing the ants to choose their ideal temperature. Regarding diapause or winter rest: Amazon ants don't experience true hibernation, but some may reduce activity during cooler or drier seasons. Without data, simply maintain stable warm conditions and adjust only if you observe clear seasonal slowing.

Frequently Asked Questions

References