First off, I've noticed the environment seems to play heavily into when the glow reflex is triggered. However, it doesn't seem to be the state of the environment that matters, so much as changes to the environment itself. In toying with the lightning bug, I had found that blowing small puffs of air toward the bug and rapid changes in lighting both triggered predictable results to the point of getting the glow to occur a specific number of times relative to the number of times each action was performed.
Next, I've noticed at points where the state of the environment was kept static, the glow did not trigger at all at any point the lightning bug remained stationary. However, the glow would consistently be triggered at points immediately before and during the bug's movements, and then discontinue right before movement ceased.
Finally, it seems that not only does movement trigger the glow, but the patterns of the glow generated by the movements varied with the complexity of the movements. For example, walking would trigger a very slow blinking, but flying triggered a more rapid pattern.
Based on these observations, I'm starting to think this idea of the glow being used for communication purposes may be an inaccurate assessment, at least as far as any sort of voluntary communication is concerned. Instead, I'm inclined to believe the glow may actually be more of an involuntary and passive response to the lightning bug's overall brain activity, as opposed to a voluntary decision to light up or not light up.
I'm actually kind of curious what our entomology-minded slashdotter's think. If my thinking on this is correct, it could offer some interesting insight into how the brains of these insects actually work. (Sort of like a primitive, always-on EEG wired directly into the brain.)
More importantly, perhaps this could be used in some manner on more complex creatures to allow for instantaneous visual feedback about the state of that creature's brain, rather than having to remove these creatures from their natural environments to observe them via other methods."