Appendix 8—figure 3. How ommatidium dimensions change during light-induced photoreceptor contractions.

The three images show the same transverse section of three Drosophila ommatidia, with their rhabdomeres appearing as six darker curvy strips. The rhabdomeres contract (cyan arrow) to light (yellow arrow, as focused by the lens), moving both (A) horizontally (back-to-front) and (B) vertically (down arrow), see Appendix 7. Because the rhabdomeres are connected to the surrounding structures by adherence junctions (Tepass and Harris, 2007) (red boxes highlight the transition areas), their contraction induces (C) moving and possibly narrowing of the aperture (green horizontal arrow) formed by the cone and pigment cells, which are directly above the rhabdomeres (lighter blue areas). Ultimately, the curvature of the lens and focal distance might also change slightly. Image modified from (Gonzalez-Bellido et al., 2011).