I've wondered about that myself, but it seems unlikely judging from the favored food plant. My suspicion is that they aren't aposemitic, with the coloring more blended to the environment that it might seem. They are actualy really well camauflaged (until you actually spot them, or one moves). There is a whole group of related Composite-feeding species (Hesperotettix, Campylacantha, etc.) that show similar coloring, and they are all amazingly difficult to see until they move. Most have the habit of holding very still, and if things get too dicey for them, they will fly or dive for cover. Dactylotum is related too, and would seem to be a blazing flag of color until you actually see them hiding among the grass and weeds. The broken coloring makes them pretty well hidden among the broken shadows of the plants.

Of course I might be totally wrong. After all, I've never eaten one to see how it tastes, or how it makes me feel.

There are very boldly patterned caterpillars (striped with various colors such as white, red, yellow, blue, green) that feed on the same plants as these hopper, and - well - I don't know about those either, but to human eyes, there is no way they are camauflaged.