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Cuckoo spit

Posted: Tuesday 20 May 2014
by Richard Jones

Sunday saw our first barbecue of the season, but as we sat munching our smoky kebabs, we were dripped on by froghopper excrement.


Sunday saw our first barbecue of the season, but as we sat munching our smoky kebabs, we were dripped on by froghopper excrement. It’s not as bad as it sounds, but still slightly disconcerting to have a cool drip land on your neck every so often.
 
Up in the apple foliage, and in the twisting vines of Clematis armandii that snake through it, we obviously have a fair colony of the very aptly named spittle bug, Philaenus spumarius. Cuckoo spit, as it is widely known, is, of course, a terrible slight on the poor non-expectorating bird, and is caused by the soft pale nymphs of these curious hopping insects. There's obviously not quite as much as is decorating the lavender hedge a few doors up the road (that’s where I took this photo), but I can make out quite a few white blobs up there.
 
Like many sap-sucking insects, Philaenus has a dilemma when it comes to excretion. Sap is nearly all water, and also has high levels of sugar, but is relatively low in protein. Sucking out the liquid nutrient, the froghopper nymph has to get through buckets of the stuff to extract enough of the sparse protein to actually grow. Aphids have a similar problem, which is why, when they pass the excess fluid, the still-sweet honeydew (barely changed from sap) drips stickily onto the leaves. A large aphid colony is likely to get bedraggled in its own mess, which is why the athletic excreters flick the droplets into the air, to rain down on whatever's below (we’ve all had that tacky drizzle on the car windscreen or the garden furniture); alternatively the sugary liquor is collected direct from their backsides by thirsty ants.

Philaenus nymphs use the copious throughput in a thoroughly ingenious way, by blowing bubbles out too, and whipping it up into the familiar froth. Inside their foamy drips they're now hidden from predators, protected from any extremes of heat or cold, and from desiccation. And if there's too much of it, it drips down onto the heads of the barbecuers below.




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lovegardening77 23/05/2014 at 20:12

I have a LOT of that this year, for the first time in the twoyears I've lived here!

Danny Lawn 23/05/2014 at 20:12

Are they very dangerous to fruit trees or just minor issues?

philippa smith2 23/05/2014 at 20:13

Pretty minor........you can always just rub them off with your fingers if so inclined

Orchid Lady 23/05/2014 at 23:06

I only said the other day on a different thread that I have never seen it in my garden (I have lived here nearly 5 years)...spoke too soon and it has been on two roses now.  I just did as Philippa said and wiped it off with my fingers (with gloves on!).

SweetPea93 25/05/2014 at 18:18

I have it all over a rose bush at the moment! I didn't know it was a bug, had a nosey at it the other day and was pretty cute for a bug!

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