Interesting Critters and Ecological Interactions
Although I have not studied them beyond what I learned in entomology classes, I have always found treehoppers to be cute and interesting animals. Often the pronotal ‘horn’ resembles a long sharp spike. The mouthparts are below the insect and facing back under the body. You can see this in this photo of a Glossonotus turriculatus as the long proboscis with the darkened line. They suck fluids from plants with this proboscis, and so are quite sedentary while feeding. The coloration and shape make them resemble plant thorns. Does this justify giving them the name ‘thorn mimics’ based upon the supposed evolutionary pressure of predators? I try to be very careful using the term ‘mimic’ because there are many things that must be tested before assuming this mechanism for a strange morphology. That is a post for another day. If you are interested in this, I would suggest an excellent study of aphids and plant defenses by Marcio and Rausher (1997) that looks at pressures exerted by insects and the possibility that this leads to defense structures on leaves.
Mauricio, R. and M.D. Rausher (1997). Experimental manipulations of putative selective agents provides evidence for the role of natural enemies in the evolution of plant defense. Evolution 51: 1435-1444.