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Nature’s Thermometer: How Crickets’ Chirping Can Help You

December 26th, 2009 Posted in Pantry & Linen Pests

Did you know not all cricket chirps are alike? Each of the 127 different species of crickets in the United States has its own unique chirp.

Listening to crickets’ chirping is one way entomologists distinguish between crickets and katydids, a related insect, and also, between different species of crickets.

The sound of crickets chirping can also help people tell what temperature it is outside, no thermometer required.

Find out:

• How they chirp
• Why they chirp
• How crickets’ chirping can help you

How Crickets Chirp

With long legs that resemble violin strings, many believe crickets rub their legs together to chirp.

In actuality, they rub their wings together in a process called “stridulation.”

A cricket does this by lifting up his left forewing, which has 50-300 ridges, in a 45 degree angle; then, he rubs his upper wing across the sharp edge of his lower wing. The membranes on the wing amplify the sound.

Crickets hear the chirping of other crickets with ears located under the knees of their front legs. They have tympanic membranes (i.e. eardrums) located in their knees that allow them to experience auditory sensations.

Why Crickets Chirp

Males are the only crickets that chirp in most species. The main objective of crickets’ chirping is to call to far away mates and court nearby females; chirping also warns potential competition to stay away, or is made when crickets fight.

Since each species has a different chirp, potential mates can distinguish between the cricket sounds and seek out a mate of the same species.

Differing cricket sounds are indicators of evolution since the differences can be linked to tiny genetic variations between species.

The sound of crickets chirping isn’t always helpful for crickets, as it also attracts a parasitic fly. The parasite deposits onto a cricket its larvae, which then burrow into the cricket’s body, where they grow and subsequently kill the cricket.

A team of researchers led by Marlene Zuk, of the University of California, Riverside, monitored crickets on Kauai, beginning in 1991, hearing fewer crickets chirping with each visit. In 2003, crickets were still abundant, but 90 percent of the males were silent, with flat wings.

The scientists believe this mutation protects crickets from the fly. Obviously, the mating behavior changed as well, since the mating call was no longer being used, but crickets were still reproducing. Females find males with flat wings since the males congregate around those that still have fanned wing instruments.

How Crickets’ Chirping Can Help You

Helps with Identification

As mentioned earlier, crickets and katydids are closely related, and it is hard to tell them apart visually. They both have long hind legs for jumping, long antennae, ears on their front legs, and wings that fold like fans.

However, a well-trained eye can identify that crickets have three segmented feet, while katydids have four. Still some species are next to impossible to distinguish without performing DNA tests.

But even an untrained ear can distinguish between these two types and each of their species by listening to their distinctive songs.

Acts as Nature’s Thermometer

Besides allowing us to distinguish between crickets and katydids and amongst cricket species, crickets’ chirping indicates what the temperature is outside. This is so because the frequency of chirping varies as temperatures rise and fall.

In 1897, physicist Amos Dolbear noticed the temperature determined the number of cricket calls he heard. The more chirps, the higher the temperature was.

Reversing this concept allows us to figure out the temperature from counting the number of cricket chirps—a useful survival technique.

To calculate the temperature in degrees Fahrenheit, The Old Farmer’s Almanac says:

1. Count the number of chirps in 14 seconds.
2. Add 40 to this number.
3. Final number is the approximate temperature.

Example: 39 chirps + 40 = 79 degrees F

To calculate the temperature in degrees Celsius:

1. Count the number of chirps in 25 seconds.
2. Divide the number of chirps by 3.
3. Add 4 to that number.
4. Final number is the approximate temperature.

Example: (39 chirps / 3) + 4 = 17 degrees C

Although helpful when outside, crickets aren’t as welcome inside. If you hear chirping inside of your home, check for an infestation, since crickets can cause damage to clothes, carpets and more.

Watch this video to learn more:

Use safe, natural home pest control, if it turns out you do have an infestation.