Social selection in the cellular slime moulds

Abstract

Starvation triggers a complex series of intercellular interactions in the cellular slime mould amoebae. As a result the amoebae aggregate, form a coherent multicellular structure with division of labour and, eventually, differentiate into a fruiting body made up of a stalk and a spore mass. Whether an amoeba dies and forms part of the stalk or becomes a stress-resistant spore depends both on pre-existing biases and on post-starvation signalling between amoebae. Mutual communication permits one amoeba to influence the phenotype, and therefore affect the fitness, of another. The implication is that social selection has been a major factor in the evolution of cooperative behaviour in these amoebae.