Insects of Great Britain
The following insects are more frequently noticeable in the garden.
These are divided into two groups, short-horns and long-horns, depending on the length of the antennae.
The short-horns are the common grasshoppers of the British Isles. They live chiefly in long grass and are vegetarians. Their chirping song, known as stridulation, is made by rubbing the hind leg against the wing.
There are 14 species, and these vary in colour, though basically they are shades of green and light brown. As their colouring is disruptive they are able to merge into their background. They measure up to 1-½ in., though the size varies with the species.
Long-horn grasshoppers are found chiefly south of the Thames. Largely arboreal, they are omnivorous, eating young buds as well as many insects, including other grasshoppers. They stridulate by rubbing their forewings together. The great green grasshopper is the largest species. The females are up to 2-½ in. long, and the males are a little shorter.
British grasshoppers do little harm and need not be feared in the garden.
Contrary to popular belief, it is probable that earwigs do little harm and even a certain amount of good. They are omnivorous—eating insect larvae as well as decaying vegetation—but are mainly nocturnal in their feeding and prefer to spend the day in some crevice or hole. Flowers often provide them with this shelter, as do the hollow stems of such plants as lupins and delphiniums. When fully grown, the common earwigs are about £ in. long, with glossy reddish-brown head and pincers, a darker brown abdomen and light brown legs.
DRAGON-FLIES AND DAMSEL-FLIES
Dragon-flies, of which there are -a species in Britain, are large, swift-flying carnivorous insects which pursue their prey on the wing. The length of their bodies is between 1-½ and 3 in. Damsel-flies are smaller, with a weaker, more fluttering flight. Both are most brightly coloured, being brilliant red, turquoise, green, yellow, black, etc.
The larvae of both live under water and in the adult stage it is normally only the powerful dragon-flies that venture far from the water.
The beautiful colours of both dragon-flies and damsel-flies add to the charm of a garden pool. They both have strong jaws for eating their victims, but neither of them sting.
All kinds are alarmingly prolific. It has been calculated that, but for the host of insects and birds which prey on them, the progeny of a single greenfly would destroy their food plant throughout the world in the course of two or three years.
The life cycle of greenflies is remarkable. During the summer there are only females, and these produce other females by parthenogenesis or virgin birth. Some of these offspring are wingless and remain on the plant on which they were born; others are fully winged and fly off to establish new colonies. Males are born in late autumn, when mating takes place. The species survives the winter only in the egg stage.
These are about.3/4 in. long and are fragile creatures with delicate transparent wings. The green lace-wing, with pale green wings and body and large bronze eyes, should be examined through a magnifying-glass for its full beauty to be seen.
It is quite common in gardens, where jt consumes large quantities of aphids.