Cuckoo-spit is formed by the young of Cercopis sp., Philaenus spumarius and others in the Aphrophoridae family, the insect is also known as the spittlebug. There are 9 British species in this family.
The fantastic feats of the adult cuckoo spit / spittlebugs
The average adult length of U. K. species is around 6 mm; average weight is around 12 mg, yet they can exert a force 100 times greater that their own body weight. To put this into perspective a fit adult human can manage only 3 times. Take off velocity is 4 m/sec., with an initial acceleration of 400 m/sec., and G force of over 400! Its hind legs are so specialized for jumping that they are useless for walking, and they get dragged behind when the insect walks.
Philaenus spumarius is around 5 - 6 mm long when fully grown, and varied in colour from yellow right through to black. The nymphs are yellow or light green. The nymphs are common from May - June, and the adults from June - October.
Cuckoo spit, spittlebug lifecycle
The female lays eggs in the crevices of dead plant stems in October or November (see the photograph on the left). The eggs hatch in the spring. The nymph climbs the stem of a plant and starts to suck sap. It secretes fluid from its rear end and turns this into foam by blowing air out of its hind spiracles (paired air holes running down the sides of the insect's body). The foam protects the young insect and stops it from drying out. The adult appears from June - November. They are brown, 5 - 7 mm long, and common on hawthorn, sorrel and other plants.
Delphicidae family, Leafhoppers
75 British species. On the right is Stenocranus minutus, a brown leafhopper.
There are around 2000 species of cicada world wide; mainly tropical and sub-tropical, but only one species in Britain. Both adults and nymphs suck sap from plants. Below right is an adult cicada, and below that an adult emerging from the final nymphal stage.
Cicadas are easily recognised by their broad head, large eyes and large size most adults being at
least 15 mm long, and in some species can be 110 mm long.
The adults have two pairs of membranous wings which are held
roof-wise over the body. The front pair being much larger than the rear pair.
Adult males can make a very loud noise when they
vibrate membranes in a pair of organs, called tymbals, on their lower abdomen. They do this to attract a mate. This is called stridulation. the noise can be heard up to 1 km away.
After mating the female lays her eggs in twigs on the host plant by cutting slits with her ovipositor. She lays between 3 and 20 eggs in each slit, and a single female can lay around 300 eggs in her lifetime. The eggs can take a long time to hatch - often over 3 months. The eggs hatch and the nymphs drop to the ground and dig into the soil. This is where they will spend most of their life sucking sap from roots.
The length of time spent as a nymph depends on the species, but it is usually a prime number, e.g. 7, 13, 17. In North America the 17 year cicada is Magicicada septendecim, and the 13 year is Magicicada cassisii or cassini. Although for some grass-feeding species it can be less that a year. This synchronus mass emergences of huge numbers of individuals is actually a defense mechanism. Cicadas are the prey of birds and many other animals, and if a huge number of food items are available for a short time, the predators are unable to eat them all. So although many cicadas are eaten, many do go on to mate and lat eggs.
Mature nymphs emerge from the soil and climb up anything handy, then moult into adults. Adult life is short; usually from as little as 3 days to 8 weeks dpending on conditions and species.
On the left is a photograph sent to me by a visitor to the site. It shows an adult cicada emerging from the exoskeleton of its final nymph stage. At the end of the final nymph stage it digs out of the soil to reach the surface. When the adult emerges the wings and outer surfaces are soft and crumpled. Blood pumped through the wings veins will expand the wings to their full extent, and the air will dry and harden the adult exoskeleton. As it dries the final colouration of the insect will emerge.
On the right is a cicada nymph, note the front legs adapted for digging in the soil