Myrmecocystus koso

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Mountain ranges of northern Mojave Desert in California and Nevada, at elevations of 6000-6600 feet. Found in Pinon-Juniper Woodland, Shadscale Scrub, and various desert communities ^[1].
• Colony Type: Likely monogyne (single queen) based on typical Myrmecocystus genus patterns, but colony structure is unconfirmed for this species ^[1].
• Size & Growth:
  • Queen: size data unavailable
  • Worker: size data unavailable
  • Colony: Large colonies observed in the wild ^[1]
  • Growth: Unknown
  • Development: Unknown, no direct studies on development timeline. (Development data is unavailable for this species.)
• Antkeeping:
  • Temperature: Keep warm, around 24-30°C with a gradient, as this species comes from hot desert habitats ^[1].
  • Humidity: Keep nest substrate moderately dry, with a small water tube for humidity if needed. Avoid damp conditions ^[1].
  • Diapause: Yes, a winter diapause is likely required based on field observations of alates in November. Provide a cool period at 10-15°C for 2-3 months during winter ^[1].
  • Nesting: Natural nesting occurs in open areas with low craters. In captivity, use Y-tong or plaster nests with dry to moderately moist substrate ^[1].
• Behavior: Workers are active foragers. Colonies are populous. Escape risk is moderate due to small size. Temperament is generally peaceful ^[1].
• Common Issues: limited availability, this is a rarely kept species with few sources., no documented captive breeding success to reference., desert habitat requirements mean humidity control is critical, too much moisture can be fatal., slow colony growth due to unknown development timeline may frustrate beginners., winter diapause requirements are inferred but not confirmed for captive colonies.

Natural History and Distribution

Myrmecocystus koso is endemic to the mountain ranges of the northern Mojave Desert, specifically found in California and Nevada at elevations between 6000-6600 feet. The type locality is in the Panamint Range in Inyo County, California. This species inhabits diverse desert communities including Pinon-Juniper Woodland at higher elevations and Shadscale Scrub at lower elevations. Nests are typically found in open areas and are usually surmounted by a low, circular crater, which may be absent due to wind or rain ^[1].

Identification and Distinguishing Features

Workers of Myrmecocystus koso resemble those of Myrmecocystus placodops but are distinctly smaller, with major workers having a head width greater than 1.7mm. The presence of numerous punctures on the face helps separate them from placodops. The species is more difficult to distinguish from Myrmecocystus romainei, to which it appears closely related. In koso workers, the punctures on the side of the face are sparser, coarser, and less well-defined than in romainei, and this part of the face is conspicuously shagreened. The pronotal hairs are longer and more slender than the mesonotal hairs in koso, while in romainei they are about equally long and thick. Both species have a pubescent third abdominal tergum, but the fourth is bare in romainei and usually pubescent in koso, except in the smallest workers ^[1].

Reproduction and Nuptial Flights

Nothing is definitively known about the mating flights of this species. However, alates of both sexes were collected from the allotype colony in early November at Wildrose Canyon in the Panamint Range. These were mostly callows (newly emerged adults), and many sexual pupae were present in the colony at that time. Since the season was already approaching winter at that altitude, researchers believed a mating flight would not occur so late in the season, and that the sexual forms would instead overwinter and fly during warm vernal weather ^[1].

Housing and Nest Setup

For captive care, provide a nest that mimics their natural desert habitat. A Y-tong nest or plaster formicarium works well for this species. The nest should have chambers scaled to their size, but specific measurements are unavailable. Keep the nest relatively dry with low humidity, typical of desert species. A small water tube can provide moisture if needed, but avoid creating damp or humid conditions inside the nest chamber. Provide a temperature gradient of 24-30°C, with the warmer end around 28-30°C and cooler areas available for self-regulation ^[1].

Feeding and Diet

Myrmecocystus honey ants are known for tending aphids and collecting honeydew, along with hunting small insects. In captivity, offer a varied diet including sugar water or honey as a carbohydrate source, and protein sources such as small insects like fruit flies or mealworms. Ensure fresh water is always available. The colony's populous nature means they will consume moderate amounts of food once established ^[1].

Seasonal Care and Overwintering

Based on the collection data showing alates and sexual pupae present in early November, this species likely requires a winter diapause period. Provide a cool period at temperatures around 10-15°C for 2-3 months during winter, typically from late November through February in the Northern Hemisphere. During diapause, reduce feeding frequency and allow the colony to slow down. After the winter period, gradually warm the colony back to room temperature to trigger spring activity ^[1].

Frequently Asked Questions

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References