Now well into autumn the activity of insects in our gardens is much reduced on what it was just a couple of months ago but on warm days, in sheltered sunny spots there will still be some insects enjoying the ‘retirement’ period of their lives by basking in the weakening sun.
One insect I frequently see in our Cornish garden in November is the dark bush cricket. In fact I quite often see these crickets on the walls of our house which is south-facing. They creep out of the vegetation and stay motionless on the wall until they have become warm enough to move around more efficiently.
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How to tell the difference between grasshoppers and crickets
Crickets and grasshoppers belong to the Order of insects named ‘Orthoptera’, a term which is derived from ‘ortho’ meaning straight and ‘ptera’ meaning wings. So they are creatures with straight wings.
Some species have long wings which they can use in conjunction with their powerful hind legs to propel themselves over great distances. Others have very short wings which are useless for flight but are kept only for the purpose of stridulation. This is the process of rubbing two parts of the body together to make a sound, a bit like running your finger nail along the top of a comb, and is used as a form of communication between grasshoppers and crickets.
The Orthoptera are split into sub-orders the most obvious of which are the grasshoppers and crickets. Grasshoppers are commonly seen in meadows where their habit of jumping large distances makes them relatively easy to spot. They have short, relatively thick antennae; they stridulate using the pegs on their hind legs and are vegetarian, mainly eating grasses.
Compared to grasshoppers, most crickets are ‘plodders’ preferring to walk rather than jump and they often stay still to avoid detection. Of the crickets found in Britain the largest are bush-crickets. They have long, thread-like antennae and are distinct from other species because their feet, or tarsi, are split into four segments.
Bush crickets are mostly diurnal, ie they are most active during daylight hours, but they are most active in the afternoon and evening, they can also be confused into stridulating under streetlights. They make their ‘song’, or stridulation, by rubbing together their forewings and they hear each other through the use of a hearing membrane on their forelegs. Bush crickets are mostly omnivorous eating leaves as well as other insects.
Female bush-crickets have long ovipositors. These are the spear-shaped extensions at the back of their abdomen which they use to stab their eggs into stems, rotting wood or into the ground where they are protected over winter until hatch next spring.
The dark bush cricket
The dark bush-cricket, Pholidoptera griseoaptera, is a medium sized bush-cricket varying in length between 13 and 20mm. Despite its name it can be quite light in colour but usually it is dark brown along its back with a greenish-yellow underside. Its wings are very short and the female has a long ovipositor which curves upwards.
It is most common in the southern half of the UK including Wales. South of the Thames it is thought to be the commonest and most widely distributed species of bush-cricket. The dark bush-cricket typically lives in hedgerows favouring brambles and coarse plants, it can also be found in nettles, marshland and ditches.
Interestingly, as the dark bush-cricket develops from an egg to an adult it sheds its skin six times and changes form slightly on each occasion. In the first stages of its development its nymph looks like a spider and although there can be no certainty as to why this happens it might help to protect it from predation.
Late in the autumn the dark bush-crickets will have laid their eggs and have little to do but feed and bask, giving us the opportunity to enjoy the sight and sound of these interesting creatures.
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