Pogonomyrmex mayri

Pogonomyrmex mayri

Pogonomyrmex mayri is a small seed-harvester ant native only to northeastern Colombia, where it lives in desert and dry deciduous forest habitats. Workers measure 1.78-2.19mm with a distinctive dark reddish-brown to brownish-black body covered in coarse striated sculpture. They have long propodeal spines and fine striae on the first gastral segment. This species is phylogenetically basal within Pogonomyrmex and belongs to its own monotypic mayri-group. Colonies are relatively small, containing 200-900 workers plus brood, and nest in soil at the base of trees or shrubs. A notable feature is their ergatoid (wingless) queen, one of the few Pogonomyrmex species with this trait, making colony establishment different from typical harvester ants.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Northeastern Colombia, specifically the Guajira-Barranquilla Xeric Scrub and Sinú Valley Dry Forest ecoregions, with records up to 835m elevation in the Sierra Nevada de Santa Marta ^[1][2]. Found in desert and dry deciduous forest habitats below 200m typically, though they tolerate more mesic conditions at higher elevations.
• Colony Type: Monogyne (single-queen) colonies with ergatoid (wingless) replacement queens documented. Only 2 of 10 excavated colonies had ergatoid queens present, suggesting they serve as replacement reproductives if the primary queen dies.
  • Colony: Monogyne
• Size & Growth:
  • Queen: 1.50-1.51mm HL (ergatoid queen is actually smaller than workers) ^[3]
  • Worker: 1.78-2.19mm HL ^[3]
  • Colony: Up to 900 workers (284-1020 total individuals including brood and males)
  • Growth: Moderate, based on colony sizes and typical Pogonomyrmex development
  • Development: Estimated 6-10 weeks based on genus patterns (Development time not directly studied for this species. Estimates based on related Pogonomyrmex species.)
• Antkeeping:
  • Temperature: Keep at 24-28°C, they are a tropical/desert species from Colombia that prefers warm conditions. A heating cable on one side of the nest creates a suitable gradient.
  • Humidity: Keep relatively dry, their natural habitat is xeric scrub and dry forest. Provide a dry outworld with a moist nest chamber for brood development. Avoid excessive moisture.
  • Diapause: No true diapause required, this is a tropical species from Colombia. However, a slight reduction in temperature during winter months (reducing to around 20-22°C) may be beneficial if colony activity slows.
  • Nesting: Soil nests in captivity work well, they prefer nests at the base of structures. A naturalistic setup with compact soil chambers or a Y-tong/plaster nest with narrow passages scaled to their small size. Nest depth of 15-22cm in the wild suggests they benefit from vertical space.
• Behavior: Workers are diurnal scavengers that forage on the surface of leaf litter or bare soil. They are seed-harvesters but also consume insects (especially termites and isopods), dead arthropods, and plant material. Workers have a painful sting, handle with care. They are moderately aggressive when defending the nest. Escape prevention is important due to their small size, use fine mesh barriers.
• Common Issues: small size means escapes are likely without fine mesh barriers, tropical species may struggle in cool, humid conditions, colonies remain relatively small compared to other Pogonomyrmex, don't expect massive colonies, painful sting, avoid handling directly, ergatoid queen founding may differ from typical claustral queens, may need to leave nest to forage

Housing and Nest Setup

Pogonomyrmex mayri is a small harvester ant that does well in compact nest setups. In the wild, they nest in soil at the base of trees or shrubs, with nests reaching 15-22cm deep and containing 2-3 chambers. For captivity, a Y-tong (AAC) nest or plaster nest with small chambers works well. The nest should have narrow passages scaled to their tiny worker size (under 2.5mm). Provide a dry to moderately humid nest chamber, these are desert/dry forest ants that prefer drier conditions. The outworld can be kept dry with just a water test tube for drinking. Because of their small size, escape prevention is critical, use fine mesh on all openings and consider Fluon barriers. ^[2]

Feeding and Diet

This is a seed-harvester ant, but their diet is more varied than just seeds. In the wild, they consume dead and dry arthropods (over 50% of diet), insects especially termites and isopods during wet seasons, flower and leaf fragments during dry seasons, and seeds make up only about 10% of their diet. In captivity, offer a mix of seeds (millet, chia, flax) and protein sources like small insects (fruit flies, small crickets, mealworms). They likely accept sugar water or honey as well. Feed protein 2-3 times per week and keep seeds available constantly. Remove uneaten prey after 24-48 hours to prevent mold.

Temperature and Heating

As a tropical species from northeastern Colombia, Pogonomyrmex mayri needs warm conditions. Keep the nest area at 24-28°C for optimal colony health and brood development. A small heating cable placed on top of the nest (never underneath to avoid drying out the nest) can create a gentle warmth gradient. Room temperature may be sufficient if your home stays in this range, but monitor colony activity, if workers seem sluggish, add gentle heating. Avoid temperatures below 20°C for extended periods. ^[1][2]

Colony Structure and the Ergatoid Queen

One of the most interesting features of P. mayri is the ergatoid queen, a wingless, worker-like queen that develops from the same larval line as workers rather than developing as a distinct caste with wings. Only 2 of 10 excavated wild colonies had ergatoid queens present, suggesting they serve as replacement reproductives if the primary queen dies or becomes unproductive. The ergatoid queen is actually smaller than workers (1.50-1.51mm vs 1.78-2.19mm) and lacks visible ocelli. This is unusual in Pogonomyrmex and makes colony establishment different from typical species. When starting a colony, you may receive an ergatoid queen rather than a large winged queen. ^[3]

Behavior and Defense

Workers are diurnal and forage actively during the day, searching for seeds and dead insects on the ground surface. They are moderate foragers that travel moderate distances from the nest. Like all Pogonomyrmex, they have a potent sting and will defend the nest aggressively if threatened. The sting is reportedly painful, so avoid direct handling and use caution when working with the colony. They are not overly aggressive away from the nest but will readily attack perceived threats. Their small size makes them quick and they can squeeze through small gaps, excellent escape prevention is essential.

Growth and Development

Colonies are relatively small compared to many Pogonomyrmex species, with wild colonies containing 200-900 workers plus 25-270 larvae and pupae and up to 28 males. Total colony size ranges from 284-1020 individuals. Males are produced regularly and have been found in colonies throughout most of the year (collected on vegetation in March, April, June, September, October, and November). This suggests they may have a different mating system than other Pogonomyrmex. Growth rate is moderate, expect several months to a year to reach 50+ workers from a founding colony.

Frequently Asked Questions

References