A comparative study of the mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri (Anura: Ranidae) from syntopic and allotopic populations

Abstract

The mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri from three syntopic and five allotopic populations was studied. All recordings were made during the mating season. We tested the hypothesis that the call of P. ridibundus from allotopic populations would differ from that in syntopic populations with P. kurtmuelleri. For the comparative analysis we used univariate and multivariate statistical methods and the following characteristics: call duration, pulse group duration, pulse group interval, pulse group period, pulse group number, minimum, maximum, fundamental and dominant frequencies and pulse energy. Analyses reveal a trait divergence in most of the studied characteristics of the signals, with stronger differentiation between P. kurtmuelleri and P. ridibundus in syntopic populations than between the two species in allotopic ones. The possible evolutionary implications of this divergence are discussed.

Keywords:

• divergence
• intraspecific speciation
• vocalization
• Pelophylax
• allopatry
• sympatry

Acknowledgements

This work is supported by the research grant 025/2012 from Sofia University “St Kliment Ohridski”. We would also like to thank the two reviewers for their helpful comments.