Myrmica striolagaster

Myrmica striolagaster

Myrmica striolagaster is a medium-sized ant native to the southwestern United States and northern Mexico. Workers measure 5.57-6.50mm and are easily recognized by the distinctive longitudinal striations at the base of their gaster (abdomen) and the longitudinally striated antennal scapes. Their body is coarsely sculptured with dense, golden pilosity, and they have robust epinotal spines. The head and alitrunk are dark ferrugineous while the abdomen is darker ^[1].

This species is notable for being one of the few Myrmica ants that inhabits dry habitats rather than the damp forest floor environments typical of most members in this genus. It serves as the host for the rare social parasite Myrmica colax, which has only been found once in Limpia Canyon, Davis Mountains, Texas ^[1].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Southwestern United States (Arizona, New Mexico, Texas, Colorado) and northern Mexico (Chihuahua). Found in pinyon pine, ponderosa pine, cedar and oak woodlands, sycamore canyons, and grasslands in forests at higher elevations ^[1][2][3][4].
• Colony Type: Single-queen colonies (monogyne). Colony structure is typical for Myrmica species.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Estimated 6-8mm based on genus typical sizes
  • Worker: 5.57-6.50mm ^[1]
  • Colony: Estimated 1000-3000 workers based on typical Myrmica colony sizes
  • Growth: Moderate
  • Development: 6-10 weeks estimated based on typical Myrmica development (Development time inferred from related Myrmica species. Brood has been observed in nests during June in New Mexico.)
• Antkeeping:
  • Temperature: Keep at 20-24°C. This species is not a true thermophile, they forage during cool periods of the day (early morning, late afternoon, and evening) rather than midday heat ^[5]. Avoid excessive heat.
  • Humidity: Low to moderate. This is one of the few Myrmica species that nests in dry habitats ^[1]. Keep substrate moderately dry, not waterlogged. Provide a moisture gradient so ants can choose their preferred humidity.
  • Diapause: Yes. Like most Myrmica species from temperate regions, they require a winter hibernation period. Provide 3-4 months of cold temperatures (5-10°C) during winter.
  • Nesting: Natural nesting: under stones in soil. In captivity, they do well in Y-tong nests, plaster nests, or test tube setups with moderate humidity. Provide a dry to moderately moist substrate. They prefer compact chambers over large open spaces.
• Behavior: Workers are active foragers and generalist predators/scavengers ^[6]. They are not aggressive but will defend their nest. They forage during cooler parts of the day, early morning, late afternoon, and evening, avoiding midday heat ^[5]. This indicates they prefer moderate temperatures rather than warm conditions. Workers have a well-developed sting for defense. Escape risk is moderate due to their medium size, standard escape prevention measures (fluon barriers, tight-fitting lids) are sufficient.
• Common Issues: dry habitat confusion, keepers often keep Myrmica too wet, this species prefers drier conditions than typical Myrmica, overheating, because they're from the southwestern US, keepers assume they need high heat, but they actually avoid midday heat and prefer cooler temperatures, hibernation failure, not providing adequate winter cooling can weaken colonies over time, small colony loss, slow growth means beginners may lose patience or overfeed, causing mold issues

Nest Preferences and Housing

In the wild, Myrmica striolagaster nests under stones in soil, often on shaded slopes near moisture but in generally drier habitats than other Myrmica species ^[1]. The type specimen was collected from a nest beneath a stone on a moist, shaded, gentle, south-facing slope beside a stream, this shows they do appreciate some moisture access even if the overall habitat is drier.

For captive care, Y-tong (acrylic) nests work well, as do plaster nests and test tube setups. Keep the nest area moderately dry, the substrate should feel damp but not wet, with some drier areas available. Unlike most Myrmica that need high humidity, this species does well with lower humidity. Provide a shallow water tube for drinking and a foraging area where you can offer food. The foraging area can be kept slightly more humid than the nest proper.

Feeding and Diet

Myrmica striolagaster is a generalist predator and scavenger ^[6]. In captivity, they readily accept protein sources like small insects (fruit flies, small crickets, mealworms) and will scavenge dead insects. They also collect honeydew and sugar sources in the wild, so you can offer sugar water or honey occasionally.

Feed them small live or dead insects 2-3 times per week, adjusting based on colony size. Remove any uneaten prey after 24-48 hours to prevent mold. A small dish of sugar water or honey can be offered weekly. Since they're not a specialized predator, they are flexible eaters, this makes them easier to feed than some specialist species. However, protein-rich foods should form the bulk of their diet for healthy brood development.

Temperature and Seasonal Care

This species has unusual temperature preferences for a Myrmica ant. Research shows they are not true thermophiles, they avoid foraging during the hottest parts of the day and instead are active during early morning, late afternoon, and evening ^[5]. This means they prefer cooler conditions than many southwestern ants.

Keep the nest at 20-24°C, avoiding temperatures above 28°C. Room temperature in most homes (around 21-23°C) is ideal. If you need to warm them, use a heating cable on one side of the nest to create a temperature gradient, never heat the entire nest. During winter, provide a hibernation period of 3-4 months at 5-10°C. This is essential for colony health and mimics their natural seasonal cycle in the southwestern mountains. Place them in a garage, basement, or refrigerator (with monitoring) during winter dormancy.

Behavior and Colony Dynamics

Workers are active foragers that search for food both individually and through recruitment. They have a well-developed sting for defense, though their sting is not dangerous to healthy humans. The colony will defend against threats by swarming and stinging.

This species is known for its low discovery capacity among Arizona ant species, they are not aggressive foragers and tend to find food more slowly than competing species ^[5]. This means you may need to leave food in the foraging area longer before assuming they've rejected it. Colonies grow at a moderate pace. Queens are long-lived and can produce workers for many years. The species hosts the rare social parasite Myrmica colax in the wild, but this is not something you'll encounter in captivity.

Frequently Asked Questions

References