The effect a natural deterrent causes in species that it didn't evolve to deter is pretty random. Even if the effect is positive sometimes, as long as its prese

The effect a natural deterrent causes in species that it didn't evolve to deter is pretty random. Even if the effect is positive sometimes, as long as its presence yields an overall fitness advantage (or at least no particular disadvantage), then evolution preserves it. Like humans can be outright killed by touching some jellyfish, while turtles just eat them. I wonder if to turtles, jellyfish taste pleasurably spicy due to what chemical poisons us, like onions taste for us, which poisons insects. Overall, they're still good deals for the jellyfish and onions, since the traits are preserved.