 The scene depicting the two pests interacting is symbolic of:
In repose, Taphetta the Ribboneer resembled a fancy giant bow on a package. His four flat legs looped out and in, the ends tucked under his wide, thin body, which constituted the knot at the middle. Of all his features, only his head had appreciable thickness and it was crowned with a dozen long though narrower ribbons. Taphetta rattled the head fronds together in a surprisingly good imitation of speech. "There are at least a hundred kinds of humans, each supposedly originating in strict seclusion on as many widely scattered planets. Obviously there was no contact throughout the ages before space travel— and yet each planetary race can interbreed with a minimum of ten others ! "Outside of your own world, there's nothing like your species, except superficially, and that's true of all other creatures, intelligent or not, with the sole exception of mankind. Actually, the four of us here, though it's accidental, very nearly represent the biological spectrum of human development. There's a corresponding span of fertility. It's reasonable to assume that, if men were set down on a hundred such worlds, they'd seem to fit in with native life-forms on a few of them. That's what happened on Earth; when Man arrived, there was actually a manlike creature there. "But there are other worlds in which humans who were there before the Stone Age aren't related to anything else there. "And so, to account for the unique race that can interbreed across thousands of light-years, you've brought in the big ancestor," commented Taphetta dryly. "Something had to distribute one species so widely and it's not the result of parallel evolution—not when a hundred human races are involved, and only the human race." Taphetta rearranged his ribbons. Man was the most numerous though not always the most advanced—Ribboneers had a civilization as high as anything in the known section of the Milky Way, and there were others—and humans were more than a little feared.
 The lengths all species will go to in order to surpass one another or protect their own status
 The potential danger that could result if intermixing becomes prevalent and social stratification becomes impossible  The reality that 'playing dead' is the best strategy for managing other threatening species who use more overt power to retain superiority  The lengths all species will go to in order to surpass one another or protect their own status  Taphetta's actualized fear that humans will use germ plasm to become biologically superior to his race