A female mimic signal type in the vibrational repertoire of male Enchenopa treehoppers

Animals vary in the complexity and size of the signal repertoire used in communication. Often, these behavioural repertoires include multiple signal types for the same process, for instance, courtship. In Enchenopa treehoppers (Hemiptera: Membracidae) mate-searching males produce plant-borne vibrational advertisement signals. Receptive females then respond to males with their own signals. Here we describe an additional signal type in the repertoire of these males. We collected nymphs in Wisconsin, USA, and recorded the spontaneous signalling bouts of adult males and duetting signals of females using laser vibrometry. Two-thirds of males produced the additional signal type, which differed in temporal and spectral features from the main male advertisement signals, whilst resembling female duetting signals in placement and acoustic features. Our findings suggest that this might be a female mimic signal. Overall, our findings highlight the diversity in the behavioural repertoire that animals may use for reproduction.