Messor erwini

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Mediterranean Spain (Catalonia), open heterogeneous shrubland at 260m elevation ^[1]
• Colony Type: Single-queen colonies likely, typical for Messor genus in Spain, though specific data unavailable for this newly described species
• Size & Growth:
  • Queen: Size data unavailable, no queen measurements published for this newly described species
  • Worker: Size data unavailable, the research provides head size measurements (CS) but not total body length. Minor workers are smaller than major workers which can develop enlarged heads ^[1]
  • Colony: 55 nests recorded at the type locality in 2018 ^[1]
  • Growth: Moderate, typical for harvester ants
  • Development: Development time unconfirmed for this species, estimated 8-12 weeks based on related Messor species (Specific development data not available for this newly described species. Estimates based on genus patterns for Mediterranean Messor species.)
• Antkeeping:
  • Temperature: Keep at 22-26°C during active season. Mediterranean origin suggests they tolerate warmer conditions. Provide a temperature gradient allowing workers to self-regulate.
  • Humidity: Low to moderate, dry to arid conditions preferred. These are harvesters from Mediterranean shrubland, not rainforest ants. Allow substrate to dry between waterings.
  • Diapause: Yes, Mediterranean species requires winter dormancy. Keep at 10-15°C for 2-3 months during winter months (November-February in Northern Hemisphere).
  • Nesting: Y-tong (AAC) nests or plaster nests work well. Provide sand or sandy soil as foraging substrate. Ensure good drainage as they prefer drier conditions.
• Behavior: Generally docile but major workers can deliver a mild sting. Form characteristic foraging trails to collect seeds, similar to Messor barbarus behavior. Workers are polymorphic, majors have enlarged heads for seed processing. Active foragers that store seeds in granaries within the nest. Escape risk is moderate, standard formicarium precautions sufficient.
• Common Issues: colonies grow slowly in the first year, patience is required with this newly described species, dry conditions are essential, too much humidity causes fungal problems, major workers may appear alarming due to size but are not particularly aggressive, winter dormancy is critical, skipping diapause weakens colonies over time, seed storage means feeding intervals can be longer than for predatory ants, limited species-specific data available, much care advice is inferred from related Messor species

Housing and Nest Setup

Messor erwini does well in standard formicarium setups. Y-tong (AAC) nests with chambers sized appropriately for their colony work well. Because they are harvester ants, provide a foraging area filled with dry to slightly moist sand or sandy soil mix. The foraging area should be spacious enough for trail formation. Use a water test tube with cotton as a hydration source, but avoid over-wetting the nest substrate, these ants prefer drier conditions. Escape prevention is straightforward as they are moderate-sized ants, but ensure connections between outworld and nest are secure.

Feeding and Diet

As harvesters, Messor erwini primarily collects seeds. Provide a variety of seeds (grass seeds, millet, poppy, etc.) as a staple food source. They will also accept protein foods like small insects (dead or alive) and cat food. Sugar water or honey can be offered occasionally but is not a primary food source for seed-eating ants. Unlike predatory ants that need constant feeding, harvesters can go longer between feedings once seeds are stored in their granaries. Observe your colony, if seeds accumulate uneaten, reduce feeding frequency. Fresh water should always be available.

Temperature and Seasonal Care

Keep Messor erwini at 22-26°C during the active season (spring through fall). A temperature gradient allows workers to choose their preferred zone. During winter, they require a diapause period, reduce temperature to 10-15°C and reduce feeding. The diapause should last 2-3 months, typically from late November through February in the Northern Hemisphere. Do not feed during diapause but ensure water is available. After winter, gradually warm the colony back to active temperatures to trigger spring activity. Sudden temperature changes should be avoided.

Colony Development

Messor erwini is a newly described species (2023), so specific development data is limited. Based on genus patterns, expect claustral founding, the queen seals herself in a chamber and raises the first brood alone on stored fat reserves. First workers (nanitics) will be smaller than normal workers. Growth rate is moderate, colonies typically take 1-2 years to reach 100 workers and several years to reach maturity. The polymorphic caste system (minor and major workers) becomes apparent once the colony reaches several dozen workers. Major workers develop as the colony grows, serving as seed processors and defenders. The species shows M. barbarus-like foraging behavior, forming organized trails ^[1].

Behavior and Temperament

These ants are generally docile and not aggressive toward keepers. Major workers can deliver a mild sting if threatened, but they are not particularly aggressive species. The most notable behavior is trail-forming, workers create visible foraging trails to collect seeds from the environment. This is a visually interesting behavior that makes Messor species popular. Workers are polymorphic: minor workers handle general tasks and brood care, while major workers use their enlarged heads to crack and process seeds for storage. Some major workers show mixed trait combinations, with red heads reminiscent of M. barbarus and angulate propodeum typical of M. capitatus ^[1].

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References