Fig. 6: Actin patterning in the developing scales of Parides arcas (A-F) and Morpho helenor (G-L).

Depth coloured images (A, D, G, J) show F-actin stained with phalloidin. Coloured images (B, C, E, F, H, I, K, L) show a merge of actin (phalloidin, green) and chitin (CBD-TMR/WGA, magenta). Location of enlarged merged images (C, F, I, L) shown by dashed boxes in (B, E, H, K). A−C P. arcas scales at ~50% of development. Large actin bundles are present between the depositing cuticle ridges in addition to a network of actin within the forming ridges. Colour depth profile (Ai) indicates a more ventral positioning of the large actin bundles (red) in comparison with the branched network within the ridges (magenta/blue). Merged images (B, C) indicate that the actin within the ridges colocalizes with the cuticle ridge layers. D−F P. arcas scales at ~65% development. The large continuous actin bundles have dissociated but some actin remains within the ridges. A second highly branched F-actin network is present at the edges of the scale and is located more internally (magenta in Gi) than the actin within the ridges (blue/green in Gi). The individual branches of actin originate from single points several microns within the scale and radiate outwards towards the scale edge. G−I M. helenor scale at 50% development. Large actin bundles are present between the depositing cuticle ridges as well as some actin present within the ridge. J−L M. helenor scale at 60% development, the large bundles of actin have dissociated. A branched actin network is now visible, especially between the cuticle ridges (L) where individual filaments are positioned at regular intervals perpendicularly to the direction of the ridge. Scale bars: (A, C, D, E, G, H, J, K) 5 μm; (Ai, Gi, I, Ji, L) 1 μm;(D, F) 10 μm; (B) 2 μm.