Cuckoo Spit - life right under your nose!

As a kid, did you ever wonder who in your neighbourhood had been running round the fields and woods spitting everywhere? Most of us will be familiar with those frothy, spittle-like blobs on grass and plant stems; but have you ever questioned what they are?

 
Evidence of someone spitting on our grass! Photo by Lucy

Recently I’ve started to discover nature on the small-scale, and I’ve quickly realised how many hidden worlds there are. There are many small signs of invertebrate life that we see every year, but we never really question. I’m going to talk about one that we tend to find disgusting, but is actually really fascinating!

So the anonymous culprit responsible for the mass spitting is actually a very clever, very inconspicuous young insect. The froth is harmless, so if you can get past the initial spell of disgust, why not investigate further?

 
Dare you look more closely & wipe it away? Photograph by Roger Joy

If you pick up a spittle-covered leaf and wipe it away, you will find a small creature hiding inside. This is actually the nymph (young) of a froghopper, which in its adult form can be a rather colourful insect that jumps up to 70cm high!

The common spittle-bug you are likely to see is called the Common Froghopper but there are other species that may live in specific places. They include this black and red species Cercopis vulnerata; the aptly named black and red froghopper! 

 
Cercopis vulnerata, Black and Red Froghopper, Photograph by Roger Tidman.

Once the egg of a froghopper hatches, the nymph will start its mission to produce spittle. The substance is often referred to as ‘Cuckoo Spit’, as it generally starts to appear around the same time that the cuckoo starts to call.

The ‘spit’ we see on plants is not actually saliva, but frothed-up plant sap. Once the little bug has ingested some sap, it will use its abdominal breathing tubes to fill it with air bubbles and surround itself in a sappy froth.
There are several very clever reasons why the froghopper has developed this strategy:

• Firstly, the spit hides the small nymph from predators while it develops; we can see in the case of humans just the sight of the spit is enough to put us off!
• Secondly, the spittle helps keep the nymph moist, as it would quickly dry up without its frothy home.
• Finally, it has even been suggested that the froth has an unpleasant taste. It is thought that the bugs may use natural plant toxins in their froth as one last effort to repel any predators brave enough to taste the spittle.

The small resident of cuckoo spit - a froghopper nymph. Photo by Lucy

So have you dared to find the spittle resident yet? Once you do, you will find a small green creature that is quite often described as ‘cute’. As well as the jumping adult, these insects get the name ‘froghopper’ because the young are often considered to resemble a tiny green frog. What do you think?


A little nymph with its 'frog-like' face. Photo by Lucy

This is one little fellow I found right by our Visitor Centre at Coombes Valley, but we have heaps all over the reserve! Come for a walk in the beautiful woodlands at Coombes Valley and see what nature you can discover on the small-scale; although please don’t spit on our plants!

RSPB Coombes Valley is open every day for visitors; please visit our website or call the office on 01538 384017 for more information.