Diet can have a strong impact on development, to test this effect the strains N2, CB4856, three strains from Orsay (JU1581, JU1944, and JU1949), and three strains from Santeuil (JU1921, JU1930, and JU1932) were grown on two different food-sources. These sources were the standard lab food, Escherichia coli OP50, and the Gram-negative plant pathogen Erwinia rhapontici. The effect of these bacteria on development could also be measured by the start of reproduction, which was delayed while feeding on E. coli. To measure the transcriptional effects, age-synchronized strains were grown for 48 hours at 20 degrees Celsius. The impact of food-source on gene expression was determined by a transcriptional ruler based on the strain N2 (E-MTAB-7019).