Thoughts on the possible function and origin of bioluminescence in the New Zealand glowworm Arachnocampa luminosa (Diptera: Keroplatidae), based on electrophysiological recordings of spectral responses from the eyes of male adults

It was established by means of the electroretinogramme method that eyes of male Arachnocampa luminosa respond to the presentation of monochromatic isophotonic light flashes with three response peaks. The eyes are maximally sensitive to light of 540 nm wavelength (green); a distinct second response peak exists to light of 460 nm wavelength (bluegreen); a third response peak exists in the near-ultraviolet. Light of a wavelength longer than 660 nm does not elicit measurable responses. The results are discussed in relation to eye anatomy and physiology as well as glowworm ecology and behaviour. It is concluded that the bluegreen light emitted by glowworm larvae is aimed at small aquatic prey, but that in the adult the light, “inherited” from the larval stage, obtained a new purpose — that of in-traspecific communication.