TROPHALLAXIS AND AGGRESSION IN THE PONERINE ANT, PONERA-COARCTATA - IMPLICATIONS FOR THE EVOLUTION OF LIQUID FOOD EXCHANGE IN THE HYMENOPTERA

Trophallaxis (i.e. the exchange of alimentary liquid among colony memb ers) plays a major role in the societies of many social Hymenoptera. F ood is often not equally distributed among nestmates but instead is di rected towards more dominant individuals by means of trophallaxis, Ant agonistic behaviour can be associated with the exchange of food, or ag gression may trigger the offering of food, even where social food exch ange does not normally occur. In orphaned colonies of the ponerine ant , Ponera coarctata, workers interact aggressively at a high frequency. They establish hierarchies soon after the removal of the reproductive queen. One of the consequences of aggression among workers is trophal laxis, which also occurs regularly, although less frequently, in queen right colonies. The connection of trophallaxis and aggression in Poner a coarctata and in many other species of the Hymenoptera is discussed. This study and various other examples show that, besides the nutritio nal function of trophallaxis, the offering of food may often serve as an appeasement behaviour during aggressive interactions. We speculate that appeasing food offers may have provided the. basis for the furthe r evolution and elaboration of trophallaxis in many social Hymenoptera .