A comparison of the energetics of foraging of three species of Leptogenys (Hymenoptera, Formicidae)

The three Leptogenys species L.nitida, L.schwabi and L.attenuata coexist in the coastal forests of South Africa and exhibit an array of foraging strategies ranging from individual foraging to group raiding. To determine whether there is a physiological basis for these strategies, the energetic cost of locomotion of individuals in these three species was determined. Carbon dioxide emission of voluntary running ants was measured using a flow‐through technique, in order to determine their metabolic rate when running. The minimum cost of transport was constant over a range of temperatures (20–35°C), and similar for all three species (common value 212.96 ± 17.35 Jkg _1 m _1 ). A comparison of the energy required to sustain representative foragers at 25°C indicated that it was energetically less expensive for L. nitida workers to forage than for the other two species. This may explain why L.nitida uses group raiding, while the other two species use individual foraging with limited recruitment for retrieval of large food items.