Polyrhachis viscosa

Polyrhachis viscosa

Polyrhachis viscosa is a medium-sized African ant measuring 5.9-7.6mm in total length ^[1]. Workers have a distinctive appearance with a uniquely widened antennal scape that forms a hood-like structure hiding the base of the first funicular segment, this feature is unique among all African Polyrhachis species ^[2]. They have long pronotal spines, short upcurved propodeal teeth, and a pair of long spines on the petiole directed upward and backward. The body is dark with sparse greyish pubescence and no erect hairs on the alitrunk and gaster. This savannah species ranges across sub-Saharan Africa from Ghana to South Africa, Kenya to Sudan, preferring open sandy areas where they nest directly in the soil ^[3].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Savannah and arid-zone species found across sub-Saharan Africa including Burkina Faso, Ghana, Kenya, Sudan, Tanzania, South Africa, and neighboring countries. Nests in sandy soil in open localities, forages on the ground and ascends low bushes, trees, and grass stems ^[3][1].
• Colony Type: Colony structure is unconfirmed. Based on typical Polyrhachis patterns, likely single-queen colonies, but this has not been directly documented.
• Size & Growth:
  • Queen: Likely 7-9mm based on genus patterns (estimated)
  • Worker: 5.9-7.6mm ^[1]
  • Colony: Unknown, likely moderate-sized colonies based on typical Polyrhachis (estimated)
  • Growth: Unknown (estimated)
  • Development: Unconfirmed, based on typical Polyrhachis patterns, likely 6-10 weeks at optimal temperature (estimated) (Development timeline has not been directly studied for this species. Related Polyrhachis species typically take 6-10 weeks from egg to worker at tropical temperatures.)
• Antkeeping:
  • Temperature: Keep at 24-28°C, these are warm-climate savannah ants that prefer stable temperatures in the mid-to-high 20s. A gentle gradient allowing them to move between warmer and cooler areas is ideal. Room temperature within this range works well, or use a heating cable on one side of the nest for additional warmth.
  • Humidity: Moderate humidity around 50-70%. As a savannah species, they prefer drier conditions than rainforest ants. Keep the nest substrate lightly moist but allow it to partially dry between waterings. Provide a water tube for drinking but avoid constant saturation.
  • Diapause: Unconfirmed, likely no true diapause given the tropical/subtropical distribution, but may show reduced activity during cooler periods. Observe your colony for seasonal slowdowns and adjust feeding accordingly.
  • Nesting: Natural nesting: subterranean, digging directly into sandy soil in open localities ^[3][4]. Captive recommendations: a Y-tong (AAC) nest or plaster nest works well. Provide a layer of sandy substrate they can burrow into. They also forage on vegetation, so include an outworld with climbing opportunities. Test tube setups work for founding colonies.
• Behavior: Workers are active foragers that search both on the ground and climb vegetation ^[3]. They are generalist feeders and likely moderately aggressive when defending the nest. Escape risk is moderate, their 6mm size means standard escape prevention measures (fluon on container rims, tight-fitting lids) are sufficient but necessary. They have pupal cocoons, which is typical for the genus ^[4].
• Common Issues: colonies may be difficult to establish from founding queens due to unknown claustral requirements, escape prevention needed, workers can climb and explore, ensure secure barriers, humidity control is important, too wet causes mold, too dry causes desiccation, limited availability in the antkeeping hobby due to African distribution, wild-caught colonies may carry parasites that affect captive survival

Nest Preferences and Housing

In the wild, Polyrhachis viscosa nests directly in sandy soil in open localities, they are subterranean nesters ^[4][3]. This means they dig their own chambers and tunnels rather than using pre-existing cavities. For captive care, provide a nest setup with a sandy substrate layer they can burrow into. Y-tong (AAC) nests with a sand chamber work well, or you can use a plaster nest with a dirt section. Since they also forage up vegetation in the wild, include an outworld with branches or mesh for climbing. Test tube setups are suitable for founding colonies, provide a damp cotton ball for humidity and offer small prey items once the queen lays eggs.

Feeding and Diet

Polyrhachis viscosa is a generalist forager that hunts and forages on the ground as well as climbing vegetation ^[3]. They likely prey on small insects and arthropods, and probably collect honeydew from aphids and scale insects. In captivity, offer a varied diet including small live insects (fruit flies, small crickets, mealworms), and sugar sources like honey water or sugar water. Based on their foraging behavior, they should accept protein prey readily. Feed founding colonies small prey items that the queen can subdue. For established colonies, offer protein 2-3 times per week and keep a sugar water source constantly available.

Temperature and Seasonal Care

As a savannah species distributed across tropical and subtropical Africa, Polyrhachis viscosa prefers warm conditions. Keep the nest at 24-28°C for optimal activity and brood development. They can likely tolerate slightly cooler temperatures but growth will slow. Provide a temperature gradient so workers can choose their preferred zone. Room temperature in most homes (around 22-24°C) is acceptable, but you may need a small heating cable or mat to reach the upper end of their preferred range. Unlike temperate species, they likely do not require a true hibernation period, but may show reduced activity during cooler months. Monitor your colony, if workers become less active and cluster together, slightly reduce feeding but maintain warmth.

Behavior and Colony Dynamics

Workers of Polyrhachis viscosa are active foragers that travel both on the ground and up vegetation ^[3]. They have distinctive morphological features including pronotal spines for defense and a uniquely widened antennal scape that distinguishes them from all other African Polyrhachis species ^[2]. The species forms part of the viscosa-group within the subgenus Myrma, characterized by their apically enlarged scape and proximally flattened first funicular joint ^[2]. Colonies likely produce alate reproductives, alate females have been recorded in Sudan during August ^[3]. Workers likely defend the nest aggressively when threatened, using their spines and potentially biting. The presence of pupal cocoons means the colony goes through complete metamorphosis ^[4].

Frequently Asked Questions

References