thumb|right|230px|Plectroctena mandibularis
Plectroctena is an Afrotropical genus of ants, with most species occurring in the rainforest zones of West and Central Africa.[1] Some species are cryptic or subterranean foragers,[1] while others forage in open grassland terrain. The workers forage singly[2] or in groups of 2 to 3.[3] They nest in the earth at varying depths, or in collapsed logs. They prey mainly on millipedes, including their young or eggs.[1]
A colony of P. lygaria (a small species of the mandibularis-group) may number in excess of 300 adults. An excavated colony in the Ivory Coast consisted of 277 workers, 8 alate queens, and 42 alate males. Consequently 15% of their number was allocated to reproductives at the specific time.[1] The colony size of P. mandibularis however, seldom exceeds 50 individuals.[1] [2]
In a colony of P. lygaria, the nest chambers are located at shallow depth, in moist soil under dense leaf litter. The deepest chamber may be located about 7 cm below the surface, with each chamber up to 1 cm in height.[1] The chambers are specialized to house either brood or prey items. Nests of the widespread species P. mandibularis however, are composed of chambers typically located 2 feet or more below the surface, with entrances that are usually marked by large piles of earth.[2] [1]
It is believed that millipede eggs may at times constitute the exclusive diet of P. lygaria,[1] while newly emerged millipede young may be an additional food source for the smaller Plectroctena species. Larger species like P. conjugata, P. mandibularis and P. minor specialize on adult millipedes.[1]