July is the month where, if you walk through a meadow, you hope to see insects pinging left and right to get out of your way. In the daytime these are most likely to be grasshoppers, but we have plenty of crickets and bush-crickets in the valley which tend to be nocturnal.
There are three other species known as groundhoppers, these live in damp sites such as the margins of ponds and rivers rather than meadows. All together the three groups are part of the Orthoptera, literally ‘straight winged’.
If they sit still, the easiest way to tell grasshoppers from crickets is the antennae or feelers. Grasshoppers tend to have antennae less than a third of their body length. Crickets and bush-crickets have much longer antennae, sometimes longer than the whole body. This is probably because the crickets operate in the dark and so cannot rely on eyesight to be aware of what is going on.
If your ears are young enough you will hear the males calling to attract females. Each species has its own distinctive call, some short repeated chirps, others longer continuous sounds. In all cases the sound is made by rubbing a scraper against a row of pegs, like running your fingernail along a comb, this is called stridulation. In crickets and bush-crickets it is the two forewings rubbing, in grasshoppers it is a leg rubbing against a wing.
The Orthopteran life cycle is a single year. After mating, the females lay their eggs, live out the summer and then die. Grasshoppers tend to bury their eggs underground, the female pushes the abdomen tip down in the soil to lay batches of eggs. Some crickets do the same but most have a long bladed ovipositor at the tip of the female abdomen and this is used to lay the eggs inside plant stems and grass leaves.
When they hatch in the spring, the young are more or less mini-adults minus any wings. They grow. moulting four or five times as they grow, and emerge as adults usually in June or July ready to find a mate.
Grasshoppers are herbivorous, as are some crickets and bush-crickets, but some are more omnivorous, feeding on plants and other insects. Some bush-crickets in southern Europe are exclusively carnivorous and have spines on their forelegs to keep hold of prey. The preying mantis is another member of the Orthoptera.
Some adults can fly, but most have wings that have only half-grown and they rely on hopping to get from place to place. This is why we need corridors such as uncut road verges to allow populations to spread and mix up the gene pool. Some adults emerge out of the final moult with larger than normal wings, called the megapterous form. These will fly and can travel great distances if the air currents are favourable. In a normal summer only about one in a hundred will be megapterous but in long hot summers they are more common.
Ed Dolphin
Related Posts:
