Disparate forms of bioluminescence from the amphipodsCyphocaris faurei, Scina crassicornis andS. borealis

Abstract

Bioluminescence from the gammarid amphipodCyphocaris faurei Barnard and the hyperiid amphipodsScina crassicornis (Fabricius) andScina borealis (Sars) was measured with a photomultiplier coupled to an integrating sphere, and with a video camera.C. faurei andS. crassicornis were collected in July 1986 and 1987 off Oahu, Hawaii;S. crassicornis was also collected in May 1987 in the northern Sargasso Sea, and in October 1988 north of Hawaii, andS. borealis was obtained in September 1989 off the southern California coast. Emission spectra were obtained with an optical multichannel analyzer. Bioluminescence ofC. faurei appeared as a secretion through integumentary pores on the telson and uropods, and as a glow from a single location on the cephalothorax. The emission spectrum was bimodal or unimodal, with distinct blue-green and orange peaks. In contrast, the bioluminescence ofS. crassicornis andS. borealis was internal and of significantly shorter duration and lower quantum emission, with a unimodal, bluegreen emission spectrum. Appropriate repetitive stimulation in all species induced temporally summated flashes with greater rise times, durations, and total quantum emission than luminescence induced by a single stimulus. The emission spectrum, flash kinetics, quantum emission, and mode of luminescence ofC. faurei are unique compared with those of all other previously investigated amphipod species.