Duetting katydids (Orthoptera: Tettigoniidae) are unique in that both the male and the female use airborne sounds for mate attraction. The presence of a female response alerts the male to her location as well as provides a signal of her motivation or willingness to mate. The purpose of this study was to characterize the male advertisement call and the female tick response in the broad-winged bush katydid, Scudderia pistillata, to understand how differing contexts affect both sexes' calls, and the implications these findings might have on mate attraction and localization. Male S. pistillata produce a complex call of increasing syllables per phrase, ranging from a single-syllabled phrase to an eleven-syllabled phrase. Males are consistent in how they add syllables to phrases in a bout and the syllable number and phrase number produced relates to an index of condition, residual weight. They also exhibit plasticity in the length of their call, varying syllable number and phrase number depending upon whose acoustic signal they perceive. Male call is most highly influenced by the presence of a female; he increases his rate of calling and the total length of his bout when hearing female ticks. When males are presented with the call of another male, he synchronizes his call to theirs, but lowers his overall acoustic energy compared to a female encounter. The implications of this behavior on male chorus structure are discussed. Analysis of S. pistillata duetting behavior demonstrates that females alter their tick number with motivation as well as the number of syllables and sound intensity of the syllables she hears. When a male hears her response he performs phonotaxis; however the number of ticks he hears after each phrase in his bout does not assist in his ability to reach the female. The importance of variability in female tick number is therefore discussed. Males also exhibit a form of mate defense by producing sounds after his phrase in the time window in which female response would fall. This acoustic mate guarding serves to confuse the location of the female for eavesdropping males.