The froghopper: a creature of extremes

In the first of a new series taking a close look at garden wildlife, nature watcher Jack Edmonds highlights a fascinating insect with a unique way of keeping predators at bay

- Jack Edmonds

It seems to appear out of nowhere - a strange bubbling froth dripping from your plant stems. Disturb this froth, and you'll find a little green froghopper nymph nestled within. Despite being known as 'cuckoo spit' - as its appearance often coincides with the first call of the cuckoo in May - the foamy stuff has nothing to do with saliva. The majority of sap-sucking insects (including aphids) feed on the sugary sap from the phloem, a plant tissue that takes the foods made during photosynthesis from the leaves to the rest of the plant. Froghoppers, on the other hand, feast on the nutrient-poor sap from the xylem, which transports (mainly) water from the roots to the leaves. In order to survive on xylem sap, the froghopper nymph must drink constantly; sometimes for 24 hours straight. The 'cuckoo spit' we see is actually the urine of the froghopper; the bubbles are formed as the urine is excreted. The froghop