Two-color fluorescence in elytra of the scale-worm Lepidonotus squamatus (Polychaeta, Polynoidae): in vivo spectral characteristic

It has been known that elytra of scale-worms show fluorescence of their cuticle structures under UV excitation. The same phenomenon was described for some other polynoid species, but all of them had “unicolor” fluorescence pattern. Here, a White Sea dweller polynoid worm Lepidonotus squamatus (Linnaeus, 1758) was shown with two-color fluorescence, glowing in green and orange. We performed spectral analyses of the fluorescent particles, called tubercles, using ten different laser lines for excitation. In case of a green tubercle we were able to highlight the presence of four different chromophores: the Blue with maximum emission at 438 nm, the Green with maximum emission at 515 nm, the Yellow with maximum emission at 582 nm, and the Deep-Red with emission peaking at 711 nm. In case of orange tubercle, together with the same 4 chromophores, that we have in green one, we can determine an additional Orange chromophore with maximum emission at 600 nm.