Is there no C line in the animal kingdom? If so we're saying spiders and cockroaches are conscious? Surely there's a distinction, and nobody really doubts eleph

Is there no C line in the animal kingdom? If so we're saying spiders and cockroaches are conscious? Surely there's a distinction, and nobody really doubts elephants, dolphins and great apes, but we can clearly see the difference in quality of C. So if there is some kind of line or distinction within the animal kingdom, where would it be? Are insects the end of mechanical behavior? Or could that line extend to small fish and crustaceans? I think the article is using the word "feeling" a little too freely here. By the same measure, There could be an experiment suggesting cockroaches get stressed, and if so, would we be so quick to say they have feelings?