Forever Blowing Bubbles

The froth of cuckoo spit puzzled layman and naturalist alike for thousands of years. John Wright uncovers the froghopper

- John Wright

It’s slightly disturbing to walk among the plants of garden or countryside on a dry summer’s day and feel the sudden touch of something cold and conspicuously wet on your hand or leg. We look down to see the telltale froth of cuckoo spit and walk on, perhaps trying to remember, if we ever knew, what the stuff is—an exudate of an insect, perhaps.

Indeed, it is the product of a froghopper (it has a vaguely frog-shaped front end), more formally a member of the superfamily Cercopoidea and sometimes known as a spittlebug. In the UK, we’re blessed with only 10 of the 2,500 species that exist worldwide. All are characterised by the froth, except one family, the tropical Machaerotidae, members of which produce a fluid filled calcareous tube instead.

I expect that many of the more curious have carefully removed the froth to see what, if anything, hides inside. such efforts reveal a tiny nymph, looking decidedly startled, with its large, widely spaced black eyes. Carefully returned to its position, it will continue to feed, make more froth and eventually proceed with its relatively straightforward transformation into adult form.