Temporal and spectral description of an additional signal type of male treehoppers

Animals vary in the complexity and size of the signal repertoire used in communication. Often, these behavioral repertoires include multiple signal types for the same process, for instance, courtship. While courting, males of plant-feeding treehoppers (Hemiptera: Membracidae) perform plant-borne vibrational signals with a frequency-modulated whine and a series of pulses. Here we describe an additional signal type in the repertoire of male Enchenopa treehoppers and compared it with other male and female signals to explore its origin and function. We collected Enchenopa binotata nymphs in meadows and forest edges in Wisconsin, USA, and reared them to maturity. We did laser vibrometry recordings of the spontaneous signaling bouts of adult males and found that the additional signal is very common as two-thirds of males produced it. This signal substantially differed in temporal and spectral features from the main male signals: do not have pulses 25% of the times, and it has a shorter durati...