Abstract
P. bahamense, G. polyedra, and P. lunula exhibit interspecies differences in stimulable and spontaneous bioluminescence. For each species the total number of photons that can be emitted upon mechanical stimulation is a constant, regardless of the time during scotophase at which stimulation occurs. Ratios of stimulable bioluminescence per organism during scotophase and photophase are as high as 950:1 for laboratory cultures and have been observed as high as 4000: 1 for natural populations of P. bahamense. Spontaneous emission in darkness shows flashing as well as low-level continuous emission. Natural populations of P. bahamense, placed in darkness during natural photophase, exhibit a dual character to their stimulable bioluminescence. Mechanical stimulation techniques are described for rapid and reproducible stimulation of bioluminescence.