SPATIAL COMPONENTS OF FORAGING BEHAVIOR IN AN AFRICAN PONERINE ANT, PALTOTHYREUS-TARSATUS

Colonies of the African stink ant Paltothyreus tarsatus located in the forest have nests with shorter horizontal galleries and a smaller tot al foraging surface than colonies located in open areas. Each solitary worker specializes on the same central or peripheral hunting zone but she does not specialize on a particular sector during group-retrievin g. The search for prey is characterized by a wandering walk with spati al parameters varying in two ways. Capture of a termite releases a pat h characterized by sinuosity and a decrease in speed of movement. In c ontrast, a failure in the course of an attempted capture releases an i ncrease in both sinuosity and speed of movement corresponding to a so- called ''reserve'' behavior. Each worker shortens her retrieving trip in comparison with her search trip and the straightness of the homing paths depends on the size and shape of the prey. Our data show that be havioral flexibility at the individual level in P. tarsatus is importa nt in determining spatial foraging strategy at the colony level.