The hunting behavior of the African ponerine ant Pachycondyla pachyderma

Abstract

The hunting behavior of the African ponerine ant Pachycondyla pachyderma, a semi-specialized centipede predator, appears well adapted to this kind of prey and shows a graded complexity according to the difficulty it has in overwhelming prey. Small prey (5 to 8 mm-long termites) were detected by contact and seized by the thorax while larger prey (≥30 mm-long centipedes) were frequently detected from a distance and seized by the anterior-most part of their body. Termites and 30 mm-long lithobiomorph centipedes were not always stung, whereas stinging and even repeated stinging was needed for 50 mm-long geophilomorphs and scolopendromorphs. Moreover, overwhelming wide and heavy scolopendromorphs, which have better defensive abilities, involved the use of additional behaviors allowing the workers to capture them safely: venom spreading, and a peculiar stinging posture, the "fatal embrace". Here the workers seize scolopendromorphs by an antenna or by one of their first legs, wrap themselves around the prey while maintaining their grip with their mandibles and legs, and slowly inject venom into the prey's ventral surface. Workers retrieve small prey solitarily while, for large geophilomorphs and scolopendromorphs, nestmates can be recruited at short range or even at long range through tandem running.