Polyrhachis latharis

Polyrhachis latharis

Polyrhachis latharis is a medium-sized arboreal ant native to West and Central Africa, found in Ghana and Congo. Workers measure 6.5-7.0mm and are entirely black with distinctive yellow-brown antennae. They belong to the alexisi species-group within the subgenus Myrma and are recognized by their somewhat trapezoidal elongate head with faintly concave sides, four spines on the petiole, and a marginate pronotum and propodeum. Unlike many ants, they have no erect hairs on their dorsal surfaces. This species is totally arboreal, living exclusively in primary forest canopies and never descending to the forest floor ^[1].

What makes P. latharis particularly interesting is its specialized arboreal lifestyle, these ants are confined to densely forested regions and are rarely encountered. They build nests in tree hollows, under bark, or among epiphytes high above the ground. Like other Polyrhachis species, they have pupal cocoons, which is unusual among Formicinae ants. However, they are known to be parasitized by the zombie ant fungus Ophiocordyceps unilateralis in Africa ^[2].

Quick Summary

• Difficulty: Hard
• Origin & Habitat: West and Central Africa (Ghana, Congo). Found exclusively in primary rainforest canopies, totally arboreal and confined to densely forested regions ^[1].
• Colony Type: Likely single-queen (monogyne) colonies based on typical Polyrhachis patterns. Colony size is unknown but likely moderate (100-500 workers based on genus).
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 6.5-7.0mm (estimated from worker size range)
  • Worker: 6.5-7.0mm ^[1]
  • Colony: Unknown, estimated 100-500 workers based on genus patterns
  • Growth: Moderate, estimated based on typical Polyrhachis development
  • Development: 6-10 weeks (estimated based on related Polyrhachis species) (Development time is not directly studied for this species. Estimates based on genus-level data for similar arboreal Polyrhachis.)
• Antkeeping:
  • Temperature: Keep warm at 24-28°C. Being arboreal tropical ants, they need stable warmth. A heating cable on one side of the nest creates a suitable gradient.
  • Humidity: High humidity (70-85%). These forest canopy ants need consistently moist conditions. Mist regularly and provide a water tube.
  • Diapause: No, being tropical arboreal ants, they do not require hibernation. Keep temperatures stable year-round.
  • Nesting: Arboreal setup is essential. Use a naturalistic arboreal setup with cork bark, twigs, or a Y-tong/plaster nest with high humidity chambers. They will not do well in ground-based nests. Provide climbing structures and bark pieces.
• Behavior: Generally calm and non-aggressive compared to many ants. Workers are active foragers in the canopy layer. They are moderate escape risks due to their size, standard barrier methods (Fluon) on smooth surfaces work well. They accept a varied diet including sugar sources and protein.
• Common Issues: arboreal nature makes captive care challenging, they need vertical space and climbing structures, high humidity requirements can lead to mold if ventilation is poor, wild-caught colonies may arrive with Ophiocordyceps fungal parasites, difficulty finding established colonies since they live in forest canopies, temperature drops below 22°C can slow or stop colony activity

Nest Preferences and Housing

Polyrhachis latharis is strictly arboreal, meaning it nests in trees rather than on the ground. In captivity, you need to replicate this vertical, canopy-dwelling lifestyle. The best setups include naturalistic arboreal enclosures with cork bark, branches, and twigs for them to climb and nest in. You can also use a Y-tong (acrylic) nest or plaster nest, but provide plenty of climbing structures and keep the nest chambers humid. These ants will not thrive in standard ground-based formicariums. The key is vertical space, they want to be up high, not walking on a flat surface. Include pieces of bark, hollow twigs, or artificial nest boxes positioned in the upper portion of the enclosure. ^[1]

Feeding and Diet

Polyrhachis ants are omnivorous, accepting both sugar sources and protein. Offer sugar water, honey, or diluted syrup regularly as a constant energy source. For protein, provide small insects like fruit flies, small crickets, mealworms, or other appropriately sized prey. Being arboreal foragers, they likely hunt small arthropods in tree canopies in the wild. Feed protein prey 2-3 times per week, and keep sugar available at all times. Remove uneaten prey after 24-48 hours to prevent mold. Some Polyrhachis species also tend aphids for honeydew, so you could offer honey water as a substitute.

Temperature and Humidity

As tropical arboreal ants from African rainforests, P. latharis needs warm and humid conditions. Keep temperatures in the range of 24-28°C (75-82°F). A slight temperature gradient allows the ants to regulate their body temperature by moving between warmer and cooler areas. Use a low-wattage heating cable on one side of the enclosure, placed on top of the nest material to warm it gently. Humidity should be high, around 70-85%. Mist the enclosure regularly and provide a water tube for drinking water. Good ventilation is essential to prevent mold while maintaining humidity, small ventilation holes or mesh work well.

Behavior and Colony Dynamics

This species is relatively calm and not particularly aggressive. Workers are active foragers that patrol the canopy layer in search of food. They have four spines on their petiole (the narrow waist section), which they may use for defense, but stinging behavior is minimal. Colonies grow moderately, you can expect a colony to reach a few hundred workers over several years. The presence of pupal cocoons is notable, as many Formicinae ants produce naked pupae. This means you may see white cocoons in the nest, which is normal for this species. Watch for signs of fungal infection (Ophiocordyceps), if a worker dies with a strange fungal stalk emerging, remove it immediately and monitor the colony. ^[2]

Acquiring and Establishing Colonies

Polyrhachis latharis is challenging to acquire because it lives exclusively in forest canopies and is rarely collected. Most available colonies are wild-caught, often from Ghana or surrounding West African countries. When obtaining a colony, inspect carefully for signs of the zombie ant fungus (Ophiocordyceps), look for dead workers with unusual fungal growth. If you find an infected ant, remove it immediately as this parasite can devastate colonies. Established colonies with a laying queen are preferable to founding colonies, which have high mortality rates. If you receive a founding queen, give her a quiet, dark, humid space and do not disturb her until workers emerge. ^[2][1]

Frequently Asked Questions

References