moving hybrid zones

Hybrid zones are of special interest to investigate the speciation process and which processes either favour or impair reproductive isolation. In passerine, mating is largely driven by the selection of the sexual partner by females which assess acoustic and visual signals. Song is a particularly interesting in this regard as this signal is learnt. This implies that there is a cultural component to its transmission, a substantial deviation from the genetic mechanisms of information transmission. This project investigated the hybrid zone between two warblers  Hippolais icterina and H. polyglotta. The zone is moving which resulted, as expected, in an asymmetrical pattern of introgression, the expanding species being the most introgressed. In sympatry these warblers exhibited bilateral song convergence though. Genetic analyses could not fully account for the geographical song variation pattern, suggesting that song learning may either limit the opportunity for reproductive isolation in sympatry. Song convergence seems to enhance social interactions between both warblers, and ultimately contribute to the receding of H. icterina. Consistently, distribution modelling suggested that the interactions between theses warblers limited their breeding ranges.

Related publications

• Engler J.O., Secondi J., Dawson D.A., Elle O., Hochkirch A. 2016 Range expansion and retraction along a moving contact zone has no effect on the genetic diversity of two passerine birds. Ecography, 39, 884-893
• Engler J.O., Roedder D., Elle O., Hochkirch A., Secondi J. 2013 Species distribution models contribute to determine the effect of climate and interspecific interactions in moving hybrid zones. Journal of Evolutionary Biology 26, 2487-2496.
• Secondi J., Bordas P., Hipsley C.A., Bensch S. 2011 Bilateral song convergence in a passerine hybrid zone: genetics contribute in one species only. Evolutionary Biology 38, 441-452.
• Secondi J., Faivre B., Bensch S. 2006 Spreading introgression in the wake of a moving contact zone. Molecular Ecology 15, 2463-2475.
• Reullier J., Perez-Tris J., Bensch S., Secondi J. 2006 Diversity, distribution and exchange of blood parasites meeting at an avian moving contact zone. Molecular Ecology 15, 753-763.
• Secondi J., Bretagnolle V., Compagnon C., Faivre B. 2003 Species-specific song convergence in a moving hybrid zone between two passerines. Biological Journal of the Linnean Society 80, 507-517.
• Faivre B., Secondi J., Frochot B., Cezilly F. 2002 Local survival and breeding ecology in an expanding population of Melodious Warbler Hippolais polyglotta. Ardea 90, 293-301.
• Secondi J., Faivre B., Kreutzer M. 1999 Maintenance of male reaction to the congeneric song in the Hippolais warbler hybrid zone. Behavioural Processes , 151-158.
• Faivre B., Secondi J., Ferry C., Chastragnat L., Cezilly F. 1999 Morphological variation and the recent evolution of wing length in the Icterine Warbler: a case of unidirectional introgression? Journal of Avian Biology 30, 152-158.