|MadSci Network: Zoology|
Hi Stephanie, Cricket chirping is the way different crickets talk to each other. The most familiar cricket songs are those you hear on a warm night in summer. What you are hearing is male crickets calling to female crickets to let them know where they are, hoping the female crickets will come find them. These male crickets are only interested in females of the same species, so to make sure that they are calling to the right females, different species of crickets will have different calls. If a female cricket hears the call of a male of the same species, she will come looking for that male. If she hears the wrong call, she will just ignore him. Male crickets will sing a different song when they meet other crickets. When two male crickets meet, the two crickets will chirp at each other as their way of fighting. Eventually one of the two crickets will run away from the other. When a male cricket meets a female cricket, the male will try to impress her by chirping a different song. By listening to the song the female can tell if the cricket is healthy and “handsome”, or whether the cricket is weak or ill. The songs crickets make are made by rubbing their wings together. Each time their wings rub they make a single note. Crickets can’t really change the notes of their songs the way a singing bird could. The only way different crickets can have different calls is to change the time between chirps or to make some chirps louder than others. When the call of a cricket is slowed down so that you can hear every individual chirp, you will hear that some chirps are loud and some chirps are soft, and that some chirps come very quickly while others come with pauses in between. As you listen to crickets singing at night, it will sound like the crickets are calling at different speeds, but what you are hearing is several different species of crickets all calling together. With careful listening and practice, the different species of crickets can be identified just from the calls they are making. The speed at which a cricket chirps will change depending on the temperature outside when you listen to them. Crickets, like most insects, are ectotherms... this means that they are not warm bodied like us, but instead are the same temperature as the air around them. When crickets get cold, they slow down, so on a cold night crickets will sing slower than on warm nights. You might think this would confuse the females, since they are only going to listen for a particular call, but the females are usually just as cold or as warm as the males and will listen for the call of a male at the same temperature as them. However, if the female cricket is warm and the male cricket is cold, the female may not recognize that the male is the same species. Instead it will be listening for a male cricket just as warm as she is. Notes: I've tried to think of some good sources for further reading, though unfortunately much of it is very technical and difficult to understand. One source I can recommend is the book "Introduction to the Study of Insects" by Donald Borror, Charles Triplehorn, and Norman Johnson. It has some good general information on cricket behavior, including their songs, and talks a bit about the different types of crickets. One of the experts in the field of cricket songs is Dr. TJ Walker at the University of Florida. His web page is a good source for examples of cricket songs... you can go to his page and get information on what the crickets look like, what songs they sing, and where in the United States they live. http://buzz.ifas.ufl.edu/crickets.htm If you are curious how temperature can change a crickets song, the page on the snowy tree cricket has samples of crickets calling on hot, warm, and cold nights. http://buzz.ifas.ufl.edu/585a.htm
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