Experts on vespid wasp behavior have long noted the significant behavioral differences between the Stenogastrinae subfamily and the group that includes Polistinae and Vespinae. And others have tried, unsuccessfully, to challenge the earlier non-genetic model of vespid wasp evolution. In 1998, German researchers J. Schmitz and R. Moritz also used a genetic analysis to propose that the subfamily Stenogastrinae was evolutionarily distinct from the Polistinae and Vespinae subfamilies.

Proponents of the non-genetic model criticized their work, however, because it relied on an analysis of less than 600 base pairs from two genes (one ribosomal RNA, the other mitochondrial DNA) and included very few representative species, some of which were unsuitable for the analysis.

The new study examined variations in fragments of four genes across 30 species of vespid wasps. Four independent statistical analyses tested the reliability of the pattern of relationships that emerged from the data.

This work confirms the ideas of Schmitz and Moritz, said Cameron, by adding to the weight of evidence that their hypothesis was accurate.

The fact that eusociality evolved independently in two groups of vespid wasps also sheds light on the complexity of evolutionary processes, Cameron said.

"Scientists attempt to make generalizations and simplify the world. But the world isnt always simple and evolution isnt simple. This finding points to the complexity of life."