Communication and recruitment in pharaoh's ant, Monomorium pharaonis (L.)

Abstract

Summary o 1. Experiments were carried out with populations of a queen and about eight workers of Monomorium pharaonis (L.) kept at constant temperature in very artificial conditions. Foodsharing occurred between the members of the group; workers fed the queen and each other, very rarely the queen fed a worker. The behaviour associated with food-sharing is described. The activity of the ants was variable and sometimes none of them moved for a few minutes, this inertia was broken by spontaneous movements of one ant which disturbed its neighbours. 2. When a new source of food (rabbit liver) was added the behaviour of the population altered. Foragers, who appeared to find the food by undirected search, returned to the nest and entered in an “excited” way, which is described. This excited behaviour caused all but one or two of the workers in the nest cell to leave the cell and feed at the liver. After a variable time the workers returned to the nest cell. The queen, who rarely foraged, was not fed at once by the returned workers, and often she solicited food without success for 20 minutes. 3. The methods by which Monomorium pharaonis workers communicate with one another are discussed in relation to those of other social insects. The significance of washing in their behaviour is also discussed.