Fig. 3

``Immunohistochemical analysis of EP in L. longissimus larvae and juveniles. a Side-view of a larva with advanced developing juvenile, showing nerve underneath the ciliary bands and the EP positive nerves in the apical lobe and in the juvenile. b Top-view of the apical part of a larva, with apical organ and ciliary band of the apical lobe, showing network of EP positive nerves. c Side-view of the apical part of a larva, showing EP positive nerve running from the apical organ towards the ciliary band. Asterisks indicate EP positive cell bodies. d Side-view of the EP positive nerve before the innervation of the ciliary band, including EP positive cell bodies of the nerve cells. Asterisks indicate EP positive cell bodies. e Innervation of the nerve underneath the ciliary band by a more proximal EP positive part. Arrows follow the nerve with strong proximal EP signal in the beginning. f Close-up of EP positive signal in the nerve underneath the ciliary of a lateral lappet after strong signal amplification. Double arrow indicates the same nerve as in (g). g Side-view of a larva with developing juvenile, showing EP positive signal in the nerve underneath the ciliary after strong signal amplification. Double arrow indicates the nerve. h Top-view of a juvenile with broad EP positive signal in the neuropil and the ventral nerve cords. i Side-view of a juvenile with broad EP positive signal in the neuropil and the ventral nerve cord. Orientation: all larval pictures are oriented with the anterior side of the developing juvenile to the left. Abbreviations: al = apical lobe, ao = apical organ, at = apical tuft, cb = ciliary band, dj = developing juvenile, ll = lateral lappet, np = neuropil, vn = ventral nerve cord. Color coding: gray/white = anti-tyrosinated tubulin staining (cilia and nerves), magenta = anti-EP staining (EP positive nerve cells), blue = DAPI staining (nuclei). Scale bars indicate length of 50 μm in A-C and G-I, and 20 μm in D-F