Environment, but not genetic divergence, influences geographic variation in colour morph frequencies in a lizard

BMC Evolutionary Biology

Research

Devi Stuart-Fox¹  Claire A. McLean²  Adnan Moussalli³ 

[1] School of BioSciences, The University of Melbourne, 2010, Parkville, VIC, Australia;School of BioSciences, The University of Melbourne, 2010, Parkville, VIC, Australia;Sciences Department, Museum Victoria, Carlton Gardens, 3053, Melbourne, VIC, Australia;Sciences Department, Museum Victoria, Carlton Gardens, 3053, Melbourne, VIC, Australia;

关键词: Aridity Index;    Colour Morph;    Colour Polymorphism;    Morph Frequency;    Throat Coloration;   

DOI  :  10.1186/s12862-015-0442-x

 received in 2015-03-26, accepted in 2015-07-30,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundIdentifying the causes of intraspecific phenotypic variation is essential for understanding evolutionary processes that maintain diversity and promote speciation. In polymorphic species, the relative frequencies of discrete morphs often vary geographically; yet the drivers of spatial variation in morph frequencies are seldom known. Here, we test the relative importance of gene flow and natural selection to identify the causes of geographic variation in colour morph frequencies in the Australian tawny dragon lizard, Ctenophorus decresii.ResultsPopulations of C. decresii are polymorphic for male throat coloration and all populations surveyed shared the same four morphs but differed in the relative frequencies of morphs. Despite genetic structure among populations, there was no relationship between genetic similarity or geographic proximity and similarity in morph frequencies. However, we detected remarkably strong associations between morph frequencies and two environmental variables (mean annual aridity index and vegetation cover), which together explained approximately 45 % of the total variance in morph frequencies.ConclusionsSpatial variation in selection appears to play an important role in shaping morph frequency patterns in C. decresii. Selection associated with differences in local environmental conditions, combined with relatively low levels of gene flow, is expected to favour population divergence in morph composition, but may be counteracted by negative frequency-dependent selection favouring rare morphs.

【 授权许可】

CC BY   
© McLean et al. 2015