I am currently working on a world with a "human" species. The planet is similar to ours and these "humans" would evolve in a similar environment.
I know that bio-luminescence appears mainly where light is scarce, still, I wonder if I can create bio-luminescent "humans" without this environmental pressure.
In my mind, they would use bio-luminescence mainly for communication and more specifically for attraction. They would develop small spots of bio-luminescence in different places (head / hands / back ...). This bio-luminescence could be used at will and its colors could also be modified slightly (between 575 & 680 nm) according to the sensations expressed.
So my question is:
With a different evolution context from ours, could this characteristic be even scientifically plausible?