The Sounds of Summer: How Do Insects Sing?

Birds are famous for their songs, and even frogs get some credit for a springtime chorus. Summertime is the season where the insects’ songs shine.

A katydid. (Photo by Suzy Lyttle)

If you think of your favorite summer activity, can you think of the sounds you hear? While swimming in the pool, you may hear the loud cicadas trilling in the trees. If you are enjoying a bonfire at night, you may hear the chirping of crickets or the katydids announcing “katy did, katy did.”


Birds have special voice boxes and frogs have vocal sacs, but what do insects have to make the trees echo their presence?


Meet the insects


I think we can all imagine a time when we had a mosquito or a fly buzzzzzz in our ear. Of course these insects make sound, but the real musicians in the insect world come from the order Orthoptera, which includes crickets, katydids and grasshoppers.


Crickets usually chirp with a short burst of notes or trill singing chirps at a fast count. Field crickets can sing at anytime, while tree crickets only sing at night. Katydids are bigger green insects that can blend in perfectly with the leaves. They are night singers that call their name but also can sound like a sprinkler making rattles, scrapes, buzzes and ticks. Grasshoppers also make those sounds, but they sing during the day. Lastly, you may think of another daytime singer, the cicada. They buzz and trill in a crescendo, sometimes one at a time and other times with a whole chorus.


Why so vocal?


Insects communicate a few things with their songs. Most of the time, it is males first telling the female where exactly he is located. Once she gets close enough, the song switches to a tune to serenade her. Another reason for vocalizations is to give others directions to the best food in the neighborhood. Calls can also claim territories or be used as a warning, signaling that danger is near.


Built-in instruments


Have you ever ran your thumb along the teeth of a comb? Or rubbed a pencil down the sides of a tin can? This is similar to how crickets, katydids and grasshoppers make their songs. The process is called stridulation, which is producing sound by rubbing together two body parts.


Crickets and katydids rub their wings together. One wing has teeth like the ones on a comb, while other is a pick that can run across the comb groves to create sound. Grasshoppers rub their legs against the edge of their forewing.


Cicadas have a different adaptation to help them get their message across. Inside their abdomens are organs called tymbals. These tymbals are located on the sides of the cicada. When the cicada contracts or squeezes its muscles, the tymbals bend. The bending resonates in a large air sac in the abdomen, creating the loud buzzes and trills. It is like if you were to pop the top of a can in and out, or if you have ever used a trainer clicker to teach your dog behaviors.


Hairs to hear


Human ears have hairs inside to help us pick up different tones and pitches. These insects may not have big ears like us, but they do have lots of hairs! Hairs located all over their bodies can pick up sounds and help determine where they are coming from.


Some insects use vibrations felt in their leg joints to hear. Others have special drum-like tympanal organs on their legs to pick up vibrations and process it into sound. You will notice the legs come up often. The legs on these insects are far apart on each side of their bodies, just like our ears are on each side of our heads. The placement helps them locate the direction the sound is coming from.


Hear it for yourself!


Not sure if you have heard all these songs? Check out these videos to put your ears to the test.


Field cricket:

Katydid:

Grasshopper:

Cicada:

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