Fluorescence of spiders and spider nets is a known
phenomenon (see links below). Normally spiders have fluorescent cuticles that contain fluorophores
(chemicals that absorb and re-emit light) as a component of the haemolymph (a
fluid similar to the blood of vertebrates).
show a specimen of the tarantula Eurypeime
spinicrus that has fluorescent eyes. It can be observed by long-wave
ultraviolet light (UV A). The fluorescence is green that means the absorbed
ultraviolet light is emitted with a wavelength of approximately 550 nm. The
fluorescence of eyes means that they contain also some fluorophores like those
in the haemolymph.