Treehoppers are often barely recognizable as living creatures, let alone as insects. Many species mimic thorns, with spikes, horns, crests, or other weird modifications to their back. Treehoppers mimic thorns to prevent predators from spotting them.
The oak treehopper (Platycotis vittata) is large, up to 2 cm including the horn on the back. It is fairly common on evergreen oaks as well as birches. The treehoppers pierce tree stems with their beaks, and feed upon the sap. The young treehoppers or nymphs prefer to feed on shrubs and grasses.
The females of this species guard their eggs and nymphs. A female has been observed chasing away wasps approximately a dozen times from her colony of nymphs. After the wasp apparently grew discouraged and flew away, the female flew to her young, and examined to see that they were uninjured.
Communication between treehoppers of one species is accomplished by vibration of the abdomen against stems or leafs.