Cuckoo or Frog spit belongs to one of a number of species of froghopper whose nymphs produce a cover of frothed-up plant sap resembling spit. The nymphs are therefore commonly known as spittlebugs. The nymphs pierce plants and suck sap causing damage. The excess filtered fluids produce an acrid froth that deters predators. The froth hides the nymph from the view of predators and parasites and regulates the temperature around the nymph. Without the froth the bug would quickly dry up. Froghoppers belong to the order of Hemipteran insects.