Mysterious damp patches on our dry garden path led me to look upwards to find the cause: water – no; sap – none that I could see; and then at last, having been dripped on, I spotted the culprits – several spittle-like masses of white foam on the twigs of the tree overhanging the path. As children we used to find these on grass and leaves and knew it by the name ‘cuckoo-spit’.
The bubbles were far too high up for a closer look – hooray for a camera!
The spittle, or viscous liquid, is excreted by the spittle bug nymph (family Cercopidae) as it feeds on plant juices, forming a protective foamy ‘home’ for the bug. They cannot survive in dry, sunshine conditions, so the foam keeps the nymphs cool for as long as they are feeding. As you can see from these images, more than one nymph can be found huddling together within the spittle mass.
The adults are known as froghoppers and they leave the foamy shelter only when they are ready to cast their skin for the last time.