Sexual selection requires intra-specific variation in the characteristics mediating mate choice. In species reliant on substrate-borne vibrational signalling (SBVS), differences in the attractiveness of individual signallers’ calls can influence relative mating success since they can indicate the quality of the sender. We used laser vibrometry and playback experiments to study duet signalling in a psyllid (Anoeconeossa bundoorensis), in particular to identify characteristics linked to female responsiveness. Signals were sex-specific with the syllables (or calls) of the smaller males attaining higher frequencies than the syllables of the larger females. Male syllables build over time with more energy in the second half ofthe call while those of females have a more uniform energy distribution. Male syllables vary in the timing of the halfway point of energy production. We used playback to examine species recognition and female responsiveness to the first and second halves ofmale calls. We demonstrated that females responded only to calls of male A. bundoorensis and that they were more likely to respond to the first half of male calls. Based on the results of our second playback experiment, we found that a gradation in energy production is more important for eliciting a female reply than a uniform distribution of energy. Our findings show that the rate of energy production facilitates differentiation between syllables which could be used to indicate the quality of individual males as mates.