The Origin of Labor Division

In Bert Hölldobler, E.O. Wilson: "The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies", p39.

... solitary bees behave like semisocial species when forced forced together experimentally. ... the coerced partners proceed variously to divide labor in foraging, tunneling and guarding. ... The division of labor appears to be the result of a preexisting behavioral groundplan in which solitary individuals tend to move from one job to another after the first is completed. In eusocial special, the algorithm is transferred to the avoidance of a job already being filled by another nestmate. It is evident that progressively providing bees and wasps are already "spring loaded" for a rapid shift to eusociality once ecological factors favor the change.