A Little Bit More
The “songs” of crickets mean different things to different people. They may tell us the end of summer or the beginning of autumn is here or might recall some distant memory, long forgotten. In any event, almost everyone has heard their calls – often so much a part of the outdoors that we tend not to even notice.
Although both of a cricket’s front wings have a file and scraper, the file is typically longer on one wing and the scraper better developed on the other. Usually the sound is produced on the closing stroke of the wings. The sound produced by a single stroke is called a pulse. Each pulse is made up of a number of individual tooth strikes of the scraper on the file and the vibrations are amplified by the wing membranes. It’s not unlike dragging a fingernail over the teeth of a comb.
Cricket and grasshopper stridulation plays an important role in their behaviors. Each species has its own song, which differs mainly in its rhythm from those of other closely related species. Many crickets produce two or more different types of songs. The loudest and most common is the “calling” song, produced both day and night by some, and serves to attract a female.
Females recognize their own species’ song and move toward the sound when ready to mate. It is necessary, however, that both male and female be at the same temperature for song recognition to occur. The pulse rate varies with temperature – higher temperature promotes a faster rate. A cold male will call more slowly than a warm female, and she may not recognize him as one of her own! Males of some species produce an aggressive song too that is used to remind others males of their territories. If males get too close, they may even fight.
Activities
Crickets Galore
Objectives: Observe cricket behavior
Materials: Small container and 6-12 crickets
Crickets are common animals in pet stores – they’re a very popular food for many animals. For just a dollar or two you should be able to obtain a dozen or so crickets. Check out this web site - members.attcanada.ca - and you’ll have info on how to get started. Place the crickets in an easy-to-see-in container (an aquarium works well) so they can be observed.
If you have some crumpled-up papers in the bottom of your container, the crickets will be able to find crevices and nooks to hide and live in. Over time, as the crickets become accustomed to their surroundings, they should become tamer and rather easy to observe.
At some point, one or more males should begin chirping and this will be the time for students to see for themselves how crickets make their “song”. You’ll want to limit the number of students watching at any one time but over a matter of days, an entire classroom should be able to see male crickets chirp. Be sure they’ve read and understood the “Cricket on the Hearth” mini-poster beforehand so they know what to look for.
Key Concepts
Structures and Functions, Reproduction, Behavior and Regulation
Questions
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