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Mating calls also take form through mechanical processes. Animals that are unable to vocalize their call may use their body to attract mates.

            In the field cricket, Gryllus integer, males rub their wings together to create a rapid trill that produces sound (1). Males individually vary in the durations of their trilling or, what is more sophisticatedly called, bout length. The bout length of each male is heritable and passed on to his future offspring. Also, females prefer to mate with males that have longer bout lengths (Hedrick, 1986). The end result is that males with longer bout lengths produce more offspring than males with shorter bout lengths.

            Other factors that influence the formation of these bout lengths include temperature and predation. In field crickets, males prefer warmer sites for mating as shown by an increase in the frequency of their mating calls when they were living in warmer climates (2). Predation also affects the mating calls of field crickets. When in a potentially dangerous environment, males cease calling for longer periods of time when interrupted by a predator cue (1). This suggests that there is an interplay between intensity of mating call and risk of predation.