Workers are roughly 8–12 mm long.
Fine-art photographic collection
Polyrhachis gagates
A spiny ant colony that can turn selected workers into living liquid-storage vessels.
About this species
Polyrhachis gagatesF. Smith, 1858
Information reviewed15 July 2026
Polyrhachis gagates is a large glossy African formicine ant. It forms sizeable ground colonies, and some workers become repletes whose abdomens expand with stored liquid food.
Taxonomy
Animalia · Arthropoda · Insecta · Hymenoptera · Formicidae · Formicinae · Polyrhachis
Accepted taxon. · checked 2026-07-15
Sub-Saharan AfricaBroad range and selected reference localities — not a complete occurrence map.
Sub-Saharan Africa
Savannah, woodland and forest-edge soils.
Workers forage above ground on vegetation and soil.
Honeydew, nectar, plant secretions and arthropods.
Large colonies; one documented nest contained more than 5,000 workers and a single queen.
What makes this species remarkable?
A documented colony contained about 5,448 workers — an enormous underground workforce organised around a single queen.
Selected workers become repletes: their gasters swell with stored liquid, converting living bodies into emergency reservoirs for the colony.
The polished black body is armed with backward-pointing thoracic spines, giving a large worker both physical defence and a silhouette unlike almost any familiar garden ant.