Pheidole humeridens

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Native to the Buenos Aires region of Argentina, found in heavily grazed pastures and open grassland areas. Also recorded in agricultural environments like eucalyptus plantations and soybean crops in the broader Pampean grasslands region ^[2][3].
• Colony Type: Colony structure is unconfirmed. No data available on whether they are single-queen (monogyne) or multi-queen (polygyne).
• Size & Growth:
  • Queen: Size data unavailable, no total length measurements documented
  • Worker: Size data unavailable, no total length measurements documented
  • Colony: Unknown, no colony size data available
  • Growth: Unknown, no development data available
  • Development: Unknown, no direct measurements or studies on development time (Development timeline has not been studied for this species)
• Antkeeping:
  • Temperature: Unknown, no specific temperature data. Based on origin in temperate to subtropical grasslands, aim for warm conditions around 22-27°C, but this is inferred and not confirmed
  • Humidity: Unknown, no specific humidity data. Provide a moisture gradient with a dry nest chamber and one small moist area, as colonies are found in open pastures ^[1]
  • Diapause: Unknown, no data on overwintering requirements. The Buenos Aires region has mild winters, so diapause may be reduced or absent
  • Nesting: In the wild, colonies build mound nests in open pastures ^[1]. For captivity, use Y-tong, plaster, or soil nests with chambers scaled to small worker size
• Behavior: Behavior is not well documented. As a Pheidole species, they likely have typical genus traits like major workers for defense and foraging. The species is adaptable to human-modified landscapes. Escape risk is moderate due to small worker size, fine mesh barriers are recommended
• Common Issues: no documented care information makes this a challenging species to keep successfully, lack of colony size data means growth expectations are uncertain, no information on founding behavior makes it difficult to establish wild-caught queens, unknown diapause requirements could lead to seasonal colony losses if kept incorrectly, small minor worker size may require fine mesh to prevent escapes

Distribution and Natural Habitat

Pheidole humeridens is known only from the Buenos Aires region of Argentina in South America. Colonies build conspicuous mound nests in heavily grazed pastures, indicating a preference for open grassland environments. Studies in nearby Rio Grande do Sul, Brazil, recorded this species across multiple farm environments and both grassland and agricultural settings, showing adaptability to human-modified landscapes ^[2][3]. This suggests the species is tolerant of some habitat disturbance but requires open ground for nesting ^[1].

Identification and Morphology

This species is a member of the Pheidole fallax group. Major workers have a brownish-yellow color with light brown on the rear abdomen, and minor workers are bicolored with medium brown on the head, gaster, and pronotum. The most distinctive feature is the dentate humerus, which gives the species its name meaning shoulder-tooth. Both castes have short propodeal spines. The presence of major workers with enlarged heads is typical of Pheidole, used for seed-crushing and colony defense ^[1].

Keeping Notes

Pheidole humeridens is one of the least documented species in the Pheidole genus, with virtually no captive care information available. This makes it an extremely challenging species to keep, even for experienced antkeepers. There is no data on colony size, development time, queen founding behavior, or specific temperature and humidity requirements. The species has only been found in the wild in Argentina, and there are no established captive colonies in the antkeeping hobby. Before attempting to keep this species, you would need to locate a wild colony in Argentina or obtain founding queens from someone who has successfully collected them. Given the complete lack of captive care data, this species cannot be recommended to any keeper at this time.

Related Species in the Region

Pheidole humeridens belongs to the fallax group, which contains several similar species across the Neotropics. Studies in southern Brazil recorded this as one of only 13 ant species that occurred on all farms and in all environments sampled, indicating it is relatively common and widespread in the broader region despite being known only from Argentina ^[3]. Related species in the fallax group may share similar biology, so keepers might look to care information for other documented fallax group species for general guidance, though significant variation likely exists.

Frequently Asked Questions

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References