title: Patterns of contact call differentiation in the panmictic East African Abyssinian White-eye Zosterops abyssinicus (Aves: Passeriformes).
abstract: Species distribution patterns range from highly disjunct to continuous, depending on their ecological demands and the availability of respective habitats. East African savannahs are mostly interconnected and ecologically comparatively homogenous and thus provide a prerequisite for a rather panmictic distribution pattern for species occurring in this habitat. The Abyssinian white-eye Zosterops abyssinicus is a savannah inhabiting bird species, representing such a continuous distribution. This species occurs in high abundances and is very mobile, and past population genetic studies have suggested that gene flow is high and genetic differentiation is low even across relatively large geographic distances. Further, only little morphological differences were found. In order to test for potential divergence in acoustic traits despite its interconnected geographic distribution, we analyzed 2795 contact calls of Z. abyssinicus, which were recorded at 19 sites across Kenya. Our data indicate weak, but significant differentiation in call characteristics across latitudinal gradients. We found strong changes in call characteristics in populations where Z. abyssinicus occurs in sympatry with its highland congener, Zosterops poliogaster. However, the changes in call characteristics in sympatry were in different directions and lead to strong differentiation of the sympatric populations to other conspecific populations potentially representing a case of cascade reinforcement. The detected spatial gradients likely result from ecological differences and balancing effects of natural and sexual selection.
authors.affiliation: Terrestrial Ecology Research Group Department of Ecology and Ecosystem Management School of Life Sciences Weihenstephan Technische Universität München D-85354 Freising Germany.
authors.forename: Jan Christian
authors.initials: JC
authors.lastname: Habel
authors.affiliation: General Zoology Institute of Biology Martin-Luther University Halle-Wittenberg D-06120 Halle (Saale) Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Husemann
authors.affiliation: Chair of Ecology and Biogeography Nicolaus Copernicus University in Toruń Pl-87-100 Toruń Poland.
authors.forename: Werner
authors.initials: W
authors.lastname: Ulrich
keywords: Acoustic communication; allopatry; character displacement; contact calls; geographic gradients; sonogram; sympatry
references.citation: Nature. 2000 Feb 24;403(6772):886-9
references.pmid: 10706284
references.citation: Evolution. 2000 Jun;54(3):998-1010
references.pmid: 10937272
references.citation: Evolution. 2000 Aug;54(4):1313-25
references.pmid: 11005298
references.citation: Evolution. 2000 Oct;54(5):1687-98
references.pmid: 11108596
references.citation: Trends Ecol Evol. 2001 Jul 1;16(7):364-371
references.pmid: 11403869
references.citation: Evolution. 2002 Sep;56(9):1849-58
references.pmid: 12389730
references.citation: Evolution. 2003 Apr;57(4):894-904
references.pmid: 12778558
references.citation: Science. 2004 Feb 13;303(5660):971-5
references.pmid: 14963320
references.citation: J Evol Biol. 2004 Mar;17(2):227-37
references.pmid: 15009256
references.citation: Evolution. 2005 Apr;59(4):705-19
references.pmid: 15926683
references.citation: Trends Ecol Evol. 2004 Mar;19(3):109-10
references.pmid: 16701237
references.citation: Ecology. 2006 May;87(5):1203-14
references.pmid: 16761599
references.citation: Evolution. 2008 Sep;62(9):2393-410
references.pmid: 18540948
references.citation: Am Nat. 2002 Mar;159 Suppl 3:S22-35
references.pmid: 18707367
references.citation: Proc Natl Acad Sci U S A. 2009 Feb 10;106(6):1863-8
references.pmid: 19181851
references.citation: Evolution. 2009 May;63(5):1155-70
references.pmid: 19210538
references.citation: Proc Natl Acad Sci U S A. 2009 May 19;106(20):8256-61
references.pmid: 19420223
references.citation: Am Nat. 1992 Jul;140(1):85-108
references.pmid: 19426066
references.citation: Ann N Y Acad Sci. 2009 Jun;1168:156-82
references.pmid: 19566707
references.citation: Q Rev Biol. 2009 Sep;84(3):253-76
references.pmid: 19764283
references.citation: Proc Natl Acad Sci U S A. 2009 Nov 17;106(46):19426-31
references.pmid: 19875692
references.citation: Ecol Lett. 2005 May;8(5):461-7
references.pmid: 21352449
references.citation: Mol Ecol. 2011 Nov;20(22):4671-82
references.pmid: 21999361
references.citation: J Evol Biol. 2014 May;27(5):826-39
references.pmid: 24617299
references.citation: Heredity (Edinb). 2014 Sep;113(3):205-14
references.pmid: 24713824
references.citation: BMC Evol Biol. 2014 Jun 02;14:115
references.pmid: 24885807
references.citation: Mol Ecol. 2014 Aug;23(16):4103-18
references.pmid: 24954273
references.citation: Mol Ecol. 2015 Mar;24(6):1172-87
references.pmid: 25677704
references.citation: Am Nat. 2015 Apr;185(4):491-506
references.pmid: 25811084
references.citation: Ecol Evol. 2015 Oct 12;5(21):4849-62
references.pmid: 26640665
references.citation: Evolution. 1999 Oct;53(5):1446-1457
references.pmid: 28565574
references.citation: Evolution. 1996 Dec;50(6):2435-2453
references.pmid: 28565650
references.citation: Evolution. 1989 Mar;43(2):362-381
references.pmid: 28568554
references.citation: Evolution. 1997 Feb;51(1):295-303
references.pmid: 28568795