Hylomyrma primavesi

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Serra do Cipó, Minas Gerais, Brazil at elevations 1100-1400m in campos rupestres (rocky savannas/grasslands) ^[1][2]
• Colony Type: Single-queen colonies with one ergatoid (wingless) queen per colony. Ergatoid queens are the only reproductive caste known, no winged queens have been documented ^[2]. Workers and intercaste specimens have limited reproductive anatomy (one pair of ovarioles, no spermatheca), while ergatoid queens have three pairs of ovarioles and a functional spermatheca ^[2].
• Size & Growth:
  • Queen: 5.73-6.05mm ergatoid queen ^[2]
  • Worker: 5.32-5.78mm ^[1]
  • Colony: up to 65 workers plus intercaste specimens per colony ^[2]
  • Growth: Unknown, no development data available
  • Development: Unknown, development has not been studied. (Eggs are whitish, semi-transparent, smooth, oval with approximately 3:1 length:width ratio. Young larvae are 1.5-1.8mm, nearly adult larvae reach 3.8-4.1mm ^[2]. No data on development duration.)
• Antkeeping:
  • Temperature: Keep at room temperature or slightly warm. Based on high-elevation campos rupestres habitat (1100-1400m), they likely prefer cooler conditions than lowland tropical ants. Start around 20-24°C and observe colony activity.
  • Humidity: Native to sandy soil in relatively open, rocky savanna. Keep nest substrate moderately moist but not waterlogged. Allow some drying between waterings ^[2]
  • Diapause: Unknown, no data on seasonal requirements. The campos rupestres experience cooler temperatures and seasonal variation, so a cool period may be beneficial.
  • Nesting: Natural nests are shallow (5.5-9cm deep) in sandy soil with a simple straight tunnel leading to a final chamber. Tube entrances are small (0.2-0.5cm), often curved, made of sand grains and grass fragments ^[2]. In captivity, a small formicarium or test tube setup with sandy substrate works well. Keep chambers appropriately sized for their medium-large size.
• Behavior: These ants are docile and non-aggressive. Workers forage solitarily over short distances (up to 4m from nest) and prefer very small prey items ^[2]. When threatened by other ants (Linepithema), they retreat and hide rather than fight, a single 2-3mm Linepithema worker can dominate a 5.3-5.8mm Hylomyrma worker ^[2]. When disturbed, workers carry brood (eggs, larvae, pupae) to safety ^[2]. They are not escape artists but standard containment is recommended.
• Common Issues: small colony size means slower population growth, don't expect rapid expansion, diet specialization on tiny insects may make feeding challenging, offer small prey items, ergatoid queen reproduction is slow, colonies remain small, solitary foraging means you may not see activity often, lack of development data makes timing uncertain, patience is required, sensitive to aggressive ant encounters, keep them away from other ant species

Housing and Nest Setup

Hylomyrma primavesi nests in shallow sandy soil in the wild, with tunnels only 5.5-9cm deep ^[2]. For captivity, use a small formicarium with sandy or loose soil substrate that allows them to dig simple tunnels. A test tube setup with a sand-filled chamber can also work, though they may prefer the option to dig. The nest entrance in the wild is very small (0.2-0.5cm diameter), often curved and made of sand grains and grass pieces ^[2]. In captivity, provide a small, inconspicuous entrance. Since colonies stay small (max 65 workers), they don't need large spaces. Keep the nest moderately humid but allow the substrate to dry partially between waterings, these are not high-humidity ants. Provide an outworld area for foraging, but since they forage solitarily over short distances, a simple setup is sufficient ^[2].

Feeding and Diet

In the wild, H. primavesi forages for very small insects including Collembola (springtails), Diptera larvae and pupae, and Coleoptera larvae and adults ^[2]. Workers also bring back minute pieces of vegetable matter and sand grains to the nest. In captivity, foragers accepted live clothes moth larvae, cocoons of parasitoid wasps, living and dead Tenebrio larvae, dead mosquitos, and dead flies ^[2]. Notably, live mosquito larvae were rejected ^[2]. They prefer tiny prey items, avoid offering large insects. A varied diet of small protein sources is ideal. Sugar sources have not been documented as accepted. Feed small prey items every few days, removing uneaten food promptly.

Temperature and Seasonal Care

This species comes from high elevations (1100-1400m) in the campos rupestres of Serra do Cipó, Brazil ^[1]. This habitat is characterized by cooler temperatures than lowland tropical areas, with rocky savanna and grassland conditions. Keep them at room temperature or slightly warm, aim for 20-24°C and observe colony behavior. If workers seem sluggish, slightly warmer temperatures may help. Do not overheat. Information on diapause or winter requirements is unknown, but the seasonal variation in their native habitat suggests they may benefit from a cooler period.

Behavior and Colony Dynamics

This species has several unusual traits that affect keeping. Most remarkably, they are the only Hylomyrma species with exclusively ergatoid (wingless) queens, winged queens have never been documented ^[2]. This means queens cannot fly to disperse and establish new colonies, instead, they likely establish in pre-existing cavities near the parent nest. Colonies are small, with up to 65 workers plus intercaste specimens ^[2]. Workers forage solitarily rather than in groups, traveling up to 4 meters from the nest ^[2]. They are docile and avoid conflict, when encountering aggressive Linepithema ants, they retreat and hide rather than fight ^[2]. When disturbed, workers carry brood (eggs, larvae, pupae) to safety ^[2]. This defensive behavior should be considered when handling or moving nests.

Understanding Ergatoid Queens

Hylomyrma primavesi is unique among Hylomyrma species for having only ergatoid queens ^[2]. Ergatoid queens are wingless females that can reproduce but developed from worker-like forms rather than the typical winged queen caste. In this species, ergatoid queens are slightly larger than workers (5.73-6.05mm vs 5.32-5.78mm) and have three pairs of ovarioles plus a functional spermatheca for storing sperm ^[2]. Workers and intercaste specimens have only one pair of ovarioles and lack a spermatheca, making them non-reproductive ^[2]. This colony structure means you will have one queen that never produces wings, the colony expands through worker production rather than dispersal. The ergatoid queen system also means colonies may grow more slowly than species with winged queens.

Frequently Asked Questions

Report an Issue

The current care sheet is based fully on literature. See inconsistencies, or something that's incorrect? Please report here, it will be resolved after review from an admin. Contributing to the blogs tab also helps providing information, to make us be able to further improve the caresheets. Thank you for your support!

References