Bees, like ants, are a specialized form of wasp. The ancestors of bees were wasps in a family which preyed on other insects. The switch from insect prey to pollen may have resulted from the capture of prey insects that were covered with pollen when they were fed to the wasp larvae. Similar behaviour could be switched to pollen collection. This same evolutionary scenario has occurred within the vespoid wasps, where the group known as "pollen wasps" also evolved from predatory ancestors. 