(A) Pupae (Pw) were injected with dsAmBurs α or dsAmBurs β, and brain samples were collected when bees reached the Pbl pharate-adult phase and after ecdysis (NE phase). (B) At the Pbl phase, the effect of dsAmBurs α is slightly more pronounced than dsAmBurs β in arresting cuticle tanning. At the NE phase, the dsAmBurs α- and dsAmBurs β-treated bees showed a softer and very little pigmented cuticle than the control bees, C. (C-F) The specificity of AmBurs α and AmBurs β dsRNAs is revealed by the significantly different levels of these transcripts in brain samples of bees injected with (C, D) dsAmBurs α or (E, F) dsAmBurs β and collected at the (C, E) Pbl phase or at the (D, F) NE phase. Transcript levels determined through RT-qPCR using AmRP49 as reference gene. Each bar represent mean ± se of four (n = 4) independent (biological) samples; each sample was prepared with a single brain. Different letters on the bars indicate statistically significant differences (Student's t-test, p<0,05).