Differences in male calling song and female mate location behaviour between urban and rural crickets

Abstract

Abstract Traffic noise is one of the selection pressures of urban habitats. Because noise interferes with acoustic communication, many studies have shown that the temporal structures of acoustic signals change depending on the noise. However, it is often unknown whether the changes are adaptive, such as changes being more easily located by females under noisy conditions. To investigate the phenomena, bend-legged ground crickets (Dianemobius nigrofasciatus) were collected from three urban and three rural habitats and reared in a common garden conditions. Male calling songs and female mate location behaviour of the progeny were measured. Urban males emitted a calling song with a higher dominant frequency and shorter chirp than did rural males. The playback experiment of female response and localization to songs of urban and rural males, controlling for noise, showed that there were no significant effects of the song on the mate location behaviour between urban and rural songs under noisy conditions. Although the song of urban males elicited a faster response of females, the effect was limited. These results indicate the change in song is not adaptive in terms of female choice. Urban females located more quickly to song under noisy conditions. The results suggest adaptive changes in female mating behaviour occur in urban habitats.