Why do crickets chirp?

How are crickets so loud? Why do they chirp at night? How are they different from grasshoppers? We’re talking crickets today with Karim Vahed, a cricket and katydid expert and entomologist (bug scientist) at the University of Derby in the United Kingdom. Professor Vahed also takes on some of your pressing insect questions: Do insects have bones? What do baby bugs like to do? Do insects drink water? Why are bugs so important?

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There are over 9,000 known species of crickets on the planet. These insects are best known for singing and hopping!
Insects are divided into different orders depending on what kind they are. Crickets are in the order known as Orthoptera, which contains grasshoppers, locusts, crickets and bush crickets, and katydids.
Crickets and grasshoppers are different! For one thing, most grasshoppers make noise by rubbing one of their legs against one of their wings. But most crickets make sound by rubbing their two forewings (their front wings) together. One wing is jagged, like a little row of teeth. And the other wing kind of scrapes up against it, making a sound.
The number of teeth on the scraper, the speed of the rubbing and how frequently they make the chirps differ depending on the species. So there are lots of different cricket songs.
Try an experiment: Get a comb and run your fingernail across it. See if you can make a sound. If you have more than one comb, or a comb with two differently sized/spaced teeth, see if they make different sounds. Does the size of the fingernail make a difference in the sound? Try giving your comb to an adult and find out!
In most cricket species, the males chirp to attract a female. And they mostly sing at night to help avoid predators.
But Karim Vahed says some studies have shown that predators like domestic house cats follow the chirps of the crickets to find and eat them!
Imagine a cricket the size of a hamster! A cricket so big it would cover the palm of your hand if you were holding it. The giant wētā [say it: WEH-tah] is that insect! There are several species of giant wētās. They all live in New Zealand and most of them are protected because they’re quite rare.
Insects are the most diverse group of animals on the planet. There are more than a million known species (about 80% of all known animals). But scientists estimate anywhere from 10 million to 80 million insect species have yet to be discovered!