Sequential co-operative load transport in the seed-harvesting ant Messor barbarus

Summary:

A mechanism for co-operative load transport was detected in the seed-harvesting ant Messor barbarus. Workers co-operated sequentially, transferring the load from one to another and thus forming what might be termed a transport chain. Although most of the colony's workers could have transported loads unaided, co-operation was prompted by the appearance of high loading ratios in the vicinity of the food source. The first worker in such a chain tended to be small or medium-sized, with a high loading ratio, while the last was larger, and had a correspondingly lower loading ratio. This strategy was of major benefit to the colony, in that it considerably reduced the time required for transport to the nest.