Fig. 5. In situ hybridizations of cryostat sections of the compound eye of H. erato using UVRh, BlueRh and LWRh digoxigenin-labeled antisense riboprobes. (A) UVRh and (B) BlueRh opsin mRNAs, respectively, detected using an alkaline phosphatase-conjugated anti-digoxigenin antibody. The insets show the magnification of the boxed region. Since the sections are consecutive, the position of the same ommatidium in A can be identified in B, as indicated by aligning the black circles. The butterflies express these two opsin mRNAs in three different ways in different ommatidia: S-S, S-M and M-M in the R1 and R2 photoreceptor cells. (C) Expression pattern of the LWRh opsin mRNA transcript. In every ommatidium in the main retina, six photoreceptor cells express the L opsin mRNA. (D) Close up view of the L opsin mRNA expression pattern in the R3-8 photoreceptor cells. Sections are at around 160 µm from the cornea. Scale bars, 50 µm (A–C); 20 µm (D).