English: Commonly known as cuckoo spit, frog spit or snake spit, this froth seen under leaves of certain shrubs is built by the nymphal form of several insects.

Contrary to common belief, the foam is not a collection of eggs. Rather they are formed during the nymphal to adult transformation phase of an insect.

The froth serves a number of purposes. It hides the nymph from the view of predators and parasites, it insulates against heat and cold, thus providing thermal control and also moisture control.

Without the froth the bug would quickly dry up. The nymphs pierce plants and suck sap causing damage, and much of the excess filtered fluids go into the production of the froth, which has an acrid taste, deterring predators. A few species are serious agricultural pests.