Sexual selection and variation: a multivariate approach to species-specific calls and preferences

• Published in: Animal behaviour 2004-11, Vol.68 (5), p.1139-1153
• Main Authors: Higgins, Laura A., Waugaman, Robin D.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal behavior; Animal communication; Animal ethology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Insects; Protozoa. Invertebrata; Psychology. Psychoanalysis. Psychiatry
• ISSN: 0003-3472; 1095-8282
• DOI: 10.1016/j.anbehav.2003.10.035

We examined geographical variation in a signal–receiver system within and between the two species of field crickets Gryllus texensis and G. rubens. We found that none of the three univariate male calling song parameters (pulse rate, trill length and intertrill interval) could separate species in allopatry, in contrast to previous reports that pulse rate is species specific. Using a multivariate measure of all three song parameters for each male, we were able to separate species in allopatric populations. In sympatry, we were not able to clearly delineate species because we found a continuous and nonbimodal distribution of both univariate and multivariate call measures. We also found males in sympatry with unique combinations of calling song parameters that do not occur in either allopatric population. We conducted playback experiments to females of both species collected in allopatry. For two kinds of tests, the species differed significantly in their strength of preference and in the direction of preferring their own species' multivariate calling song. All calling song parameters were highly repeatable, while female mate choice behaviours were not. All calling song parameters varied with season (spring versus autumn) in these bivoltine species. Additional analysis to understand the variation in calling song revealed differences in male call dominant frequency.