Multivariate sexual selection on male song structure in wild populations of sagebrush crickets, Cyphoderris strepitans (Orthoptera: Haglidae)

• Published in: Ecology and evolution Vol. 3; no. 10; pp. 3590 - 3603
• Main Authors: Ower, Geoffrey D., Judge, Kevin A., Steiger, Sandra, Caron, Kyle J., Smith, Rebecca A., Hunt, John, Sakaluk, Scott K.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.09.2013; Blackwell Publishing Ltd
• Subjects: Acoustics; Animal behavior; Animal reproduction; Auditory system; Communication; Crickets; Cyphoderris strepitans; Females; Fitness; fitness surface; Gryllidae; Laboratories; Males; mate choice; Multivariate analysis; National parks; Original Research; Orthoptera; Playback; Populations; Recording; selection gradient; Sexual selection; signal; Song; Studies; Success; Grand Teton; fitness surface; selection gradient; mate choice; signal; Communication
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.736

While a number of studies have measured multivariate sexual selection acting on sexual signals in wild populations, few have confirmed these findings with experimental manipulation. Sagebrush crickets are ideally suited to such investigations because mating imposes an unambiguous phenotypic marker on males arising from nuptial feeding by females. We quantified sexual selection operating on male song by recording songs of virgin and mated males captured from three wild populations. To determine the extent to which selection on male song is influenced by female preference, we conducted a companion study in which we synthesized male songs and broadcast them to females in choice trials. Multivariate selection analysis revealed a saddle‐shaped fitness surface, the highest peak of which corresponded to longer train and pulse durations, and longer intertrain intervals. Longer trains and pulses likely promote greater mate attraction, but selection for longer intertrain durations suggests that energetic constraints may necessitate “time outs”. Playback trials confirmed the selection for longer train and pulse durations, and revealed significant stabilizing selection on dominant frequency, suggesting that the female auditory system is tightly tuned to the species‐specific call frequency. Collectively, our results revealed a complex pattern of multivariate nonlinear selection characterized primarily by strong stabilizing and disruptive selection on male song traits. Multivariate sexual selection was measured on the songs of sagebrush crickets captured from wild populations, and female preference for the measured song characters was tested with synthesized male songs broadcast to females in choice trials. Selection favored males producing songs with longer train and pulse durations (PD), but also longer intertrain intervals, suggesting an energetic constraint that necessitates “time outs” from bouts of singing. Playback trials confirmed selection for longer train and PDs, and revealed significant stabilizing selection on dominant frequency, suggesting that the female auditory system is tightly tuned to the species‐specific call frequency.