Secret lives in blobs of foam
Published 21/06/2015 | 02:30
In the night, a fox comes to a wild garden looking for a drink.
Old receptacles are turned over. Water used to be left for birds but the householder has been away. There is a young oak tree with branches gently swaying, leaves twinkling in the afternoon sun like jewels.
Wild meadow grasses move and bend in unison. Changing colour as days pass… cocksfoot, sedges, foxtails, dog's tails, fescues, sweet vernal and Yorkshire fog - names plucked from the air that once filled fields with wild richness and made sweet hay for cattle.
In a rural place where there is mature timber, a long-eared owl moves in the dusk. It is a rare sight. Rarer still would be an owlet which may be placed by a parent in a tree nook during nest dispersal. The little ones doze during daylight occasionally opening eyes buried in a fluffy ball. At twilight, a dead mouse is delivered by parents, guarding like fusiliers.
The grasses, curled docks and ribworth plantains are also homes to secret other lives identified only by tiny blobs of foam. These are called "cuckoo spits" but have nothing to do with that brood parasite which is now preparing to leave town, or, rather, the country: "In June I change my tune/In July far, far I fly/In August away I must."
If you look carefully you may see the spit, clinging to a flower stalk or grass stem. There is a living creature hiding within and it may be found when the blob is poked. This is the larva and perfect miniature of a bug called a frog-hopper (philaenus spumarius), a relative of the aphid, which looks like a tiny frog, with a plump shape, powerful back legs and bulging eyes. It has a frog-like leap also.
Cuckoo-spit is produced in the same way as bubbles are blown in a children's game. Frog-hoppers suck plant sap and excess sugary fluid, honeydew, is voided. This forms a film over an abdominal cavity into which the insect's breathing tubes open. Air is exhaled through the cavity to blow the honeydew into bubbles as a sticky fluid exudes so that they will cling to the stems of leaves and plants.
The spit is, in effect, a cocoon protecting the larva from predation and from drying up as it sucks its nourishment from the growth it is glued to.
The English naturalist Peter Marron says this is a "heroic example of insect flatulence", with the idea of an animal building a shelter "by farting into its food" never failing to entertain natural history students!
Two hundred years ago, the poet John Clare knew the hopper grubs as 'wood seers' or 'wood prophets', weather omens for country folk. He called them "shepherd's weather glasses" as when the insect's head is upwards it indicates fine days ahead and when downwards the opposite is to be expected.
The apparent excellent protection of the spit cocoon is not entirely secure. Ants are attracted to the sugary waste and there is a small wasp which can penetrate the bubbles and drag out the young hoppers to feed its own larvae.
Nature, in tooth and claw, also operates down among the slender stems of grasses and flowers.
* I wish to thank those readers who have kindly forwarded pictures of young animals, and birds, which have fallen from nests, and vistas of wild flowers, and who have also taken the trouble to write in to the Letters to the Editor page on topics mentioned here