The dramatic difference in gonad size between honey bee queens and their female workers in response to their distinct diets requires the switching on of a specific genetic program, according to a new study publishing March 21 in the open-access journal PLOS Biology by Annika Roth and Martin Beye of Heinrich-Heine University in Dusseldorf and colleagues. The finding is likely to allow more detailed analysis of the interplay of genes and nutrition that drive caste dimorphism in honey bees.