Froghoppers or Spittlebugs (Cercopoidea)
The 3,000 or so species of Frog or Spittlebugs are best known for the nymphal stage, which produces a cover of foamed-up plant sap visually resembling saliva; the nymphs are known as spittlebugs and their foam as cuckoo spit, frog spit, or snake spit.
The characteristic spittle production is related with the unusual trait of xylem feeding. Whereas most insects that feed on sap feed on the nutrient-rich fluid from the phloem, Cercopidae utilize the much more dilute sap flowing upward from the roots via the xylem. The large amount of excess water that must be excreted and the evolution of special breathing tubes allow the young spittlebug nymphs to grow in the relatively protective environment of the spittle. Normally an animal should not be able to survive on a diet so low in nutrients, but the insects’ digestive system has two symbiotic bacteria that provides them with the essential amino acids.
The foam serves several purposes. It hides the nymph from the view of predators and parasites, and it also works as an insulator against heat and cold, it also provides thermal and moisture control, without the foam, the insect would quickly dry up.
Adult froghoppers are amazing acrobats, and they can jump from plant to plant; some of them can jump up to 70 cm vertically: a more impressive performance relative to body weight than fleas. Spittlebugs can jump 100 times their own length.
Many species of froghoppers resemble leafhoppers, but they can be distinguished by the possession of only a few stout spines on the hind tibiae, where leafhoppers have a series of small spines.
Although many froghoppers have cryptic coloration, many species of the family Cercopidae are brightly colored, with some combination of red, red-orange, yellow, and black, perhaps representing warning coloration associated with reflex bleeding.