Fig. 2

Difference between the cuticle before and shortly after moulting in Phrynus longipes. Some hours after moulting (left column) the cuticle is highly wettable by water droplets (arrowhead) (see also video Additional file 3: Video S2). The cuticle lacks the granules and is rather smooth on the microscale, except for small denticles (den) that help in arresting the later secretion layer. There are two different gland openings, the 2-lipped major (maj) and the pore-like minor (min) one. Between moultings (right column), water droplets are completely repelled (arrowhead) by the cuticle. The secretion layer is visible, as white ‘powder’ (arrowhead), composed of wrinkled granules (gra), creating a micro- and nano-roughness