[Terr_]

> They also illustrate the evolution of this

One of my pet-peeves: Certain science fiction writers (often amateur) posit that humans will greatly impress aliens with our willingness--no, zeal--to consume capsaicin, a terrible death substance all sentient races flee from etc.

This is nonsense since it's basically an narrowly targeted false-alarm trick between relatively closely related creatures. It's not acidic, caustic, corrosive, etc.

> this protein

Just to head off the ambiguous phrasing here: Capsaicin itself is not a protein, but a much simpler kind of chemical.

https://en.wikipedia.org/wiki/Phenylpropanoid