The relative level of mRNA expression of the eight candidate reference genes.

<p>The data are presented as mean cycle threshold (Ct) values and shown as box-whisker plots. The boxes represent the inter quartile range of the mean Ct values, while the bars represent the maximum and minimum Ct values. The dotted line represents the mid-hinge and the scattered points represent the abnormal data. (A) Developmental stages I – III; (B) developmental stage I; (C) developmental stage II; (D) metamorphosis stage III; (E) different tissues; (F) chemical treatment.