Specificity of cicada calling songs in the genus Tibicina (Hemiptera: Cicadidae)

Abstract

Abstract. Males of Tibicina cicada species produce a sustained and monotonous calling song by tymbal activity. This acoustic signal constitutes the first step in pair formation, attracting females at long range, and is involved in male–male interactions. The specificity of this signal was investigated for the first time for seven species and one subspecies of Tibicina occurring in France. This analysis was achieved by describing tymbal anatomy, tymbal mechanism and calling song structure. Male calling songs are emitted following the same general scheme: tymbals are activated alternately and the successive buckling of the sclerotized ribs that they bear produces a regular succession of groups of pulses. The structural and mechanical properties shared by Tibicina species and subspecies lead to a considerable uniformity of the signal shape. Nevertheless, a principal component analysis applied to eight temporal and three frequency parameters revealed differences between the signals of the species studied. In particular, calling songs differed in groups of pulse rate and/or in peak of the second frequency band (carrier frequency). These acoustic differences are probably linked to differences in the numbers of tymbal ribs and body size. Groups of pulse rate and/or peak of the second frequency band could encode specific information. However, Tibicina calling songs may not act as distinct specific‐mate recognition systems and may not play a leading role in the mating isolation process; rather, they might merely belong to a complex set of specific spatial, ecological, ethological and morphological characters that ensure syngamy.