Froghoppers are a group of insects, related to cicadas, aphids and bed bugs. Their larvae feed on plant sap, but unlike those of most insects, which feed on the nutrient–rich fluid from the phloem, froghopper larvae use the much more dilute sap that flows upwards from the roots via the xylem. This means that they need to excrete a large amount of excess water, and they have evolved special breathing tubes which allow them to produce spittle in the form of a foam – which hides the nymph from the view of predators and parasites, and insulates them against extremes of temperature.
© Haydn Thompson 2022