|Site types that use this protocol||
Two species of spittle bug, Philaenus spumarius and Neophilaenus lineatus, are both widespread and common throughout the United Kingdom. Their nymphs, which are xylem feeders, are surrounded by a mass of froth or spittle which the nymphs produce by forcing air into a fluid exuded from the anus. As well as providing some protection from predators, the presence of the spittle makes the nymphs visible and therefore relatively easy to sample. There is a solid background of published ecological work on these species both at lowland and at upland sites. In addition to estimating an index of nymph density, the Protocol involves the sampling of colour morphs of P. spumarius adults. The colour polymorphism is mainly determined by a series of closely linked genes; it is likely that the proportions of morphs are environmentally determined and are therefore good indicators of environmental change.
Nymph density and adult colour morphs assessed annually.