Amphibians Do Not Follow Bergmann's Rule

Abstract The tendency for organisms to be larger in cooler climates (Bergmann's rule) is widely observed in endotherms, and has been reputed to apply to some ectotherms including amphibians. However, recent reports provide conflicting support for the pattern, questioning whether Bergmann's clines are generally present in amphibians. In this study, we measured 96,996 adult Plethodon from 3974 populations to test for the presence of Bergmann's clines in these salamanders. Only three Plethodon species exhibited a significant negative correlation between body size and temperature consistent with Bergmann's rule, whereas 37 of 40 species did not display a pattern consistent with this prediction. Further, a phylogenetic comparative analysis found no relationship between body size and temperature among species. A meta-analysis combining our data with the available data for other amphibian species revealed no support for Bergmann's rule at the genus (Plethodon), order (Caudata), or class (Amphibia) levels. Our findings strongly suggest that negative thermal body size clines are not common in amphibians, and we conclude that Bergmann's rule is not generally applicable to these taxa. Thus, evolutionary explanations of Bergmann's clines in other tetrapods need not account for unique life-history attributes of amphibians.

[1]  Xiao-Hua Zhou,et al.  Statistical Methods for Meta‐Analysis , 2008 .

[2]  M. Rodríguez,et al.  Energy and interspecific body size patterns of amphibian faunas in Europe and North America: anurans follow Bergmann's rule, urodeles its converse , 2007 .

[3]  T. Tregenza,et al.  Body size evolution in South American Liolaemus lizards of the boulengeri clade: a contrasting reassessment , 2007, Journal of evolutionary biology.

[4]  D. Adams.  Organization of Plethodon salamander communities: guild-based community assembly. , 2007, Ecology.

[5]  J. Wiens,et al.  RAPID DIVERSIFICATION, INCOMPLETE ISOLATION, AND THE “SPECIATION CLOCK” IN NORTH AMERICAN SALAMANDERS (GENUS PLETHODON): TESTING THE HYBRID SWARM HYPOTHESIS OF RAPID RADIATION , 2006, Evolution; international journal of organic evolution.

[6]  Link Olson,et al.  Ecotypic variation in the context of global climate change: revisiting the rules. , 2006, Ecology letters.

[7]  M. A. Olalla‐Tárraga,et al.  Broad‐scale patterns of body size in squamate reptiles of Europe and North America , 2006 .

[8]  R. Walters,et al.  The Temperature‐Size Rule in Ectotherms: May a General Explanation Exist after All? , 2006, The American Naturalist.

[9]  G. Measey,et al.  Bergmann’s rule and the terrestrial caecilian Schistometopum thomense (Amphibia: Gymnophiona: Caeciliidae) , 2006 .

[10]  J. L. Parra,et al.  Very high resolution interpolated climate surfaces for global land areas , 2005 .

[11]  Lee FitzGerald,et al.  The importance of phylogenetic scale in tests of Bergmann's and Rapoport's rules: lessons from a clade of South American lizards , 2005, Journal of evolutionary biology.

[12]  T. Vukov,et al.  11. Bergmann's Rule is Size-Related in European Newts ( Triturus ) , 2005 .

[13]  A. Laurila,et al.  Do common frogs (Rana temporaria) follow Bergmann's rule? , 2005 .

[14]  Bradford A. Hawkins,et al.  Bergmann's rule and the mammal fauna of northern North America , 2004 .

[15]  K. G. Ashton.  Sensitivity of Intraspecific Latitudinal Clines of Body Size for Tetrapods to Sampling, Latitude and Body Size1 , 2004, Integrative and comparative biology.

[16]  A. Dunham,et al.  Bergmann’s Clines in Ectotherms: Illustrating a Life‐History Perspective with Sceloporine Lizards , 2004, The American Naturalist.

[17]  A. Queiroz,et al.  THE PHYLOGENY OF A SPECIES‐LEVEL TENDENCY: SPECIES HERITABILITY AND POSSIBLE DEEP ORIGINS OF BERGMANN'S RULE IN TETRAPODS , 2004, Evolution; international journal of organic evolution.

[18]  C. S. Schäuble.  Variation in body size and sexual dimorphism across geographical and environmental space in the frogs Limnodynastes tasmaniensis and L. peronii , 2004 .

[19]  Aaron M. Ellison,et al.  A Primer of Ecological Statistics , 2004 .

[20]  T. Dayan,et al.  Carnivores, biases and Bergmann's rule , 2004 .

[21]  B. Manly,et al.  Latitudinal patterns in European ant assemblages: variation in species richness and body size , 1993, Oecologia.

[22]  A. Dunham,et al.  The Temperature‐Size Rule in Ectotherms: Simple Evolutionary Explanations May Not Be General , 2003, The American Naturalist.

[23]  C. Feldman,et al.  BERGMANN'S RULE IN NONAVIAN REPTILES: TURTLES FOLLOW IT, LIZARDS AND SNAKES REVERSE IT , 2003, Evolution; international journal of organic evolution.

[24]  Shai Meiri,et al.  On the validity of Bergmann's rule , 2003, Journal of Biogeography.

[25]  M. Belk,et al.  Bergmann’s Rule in Ectotherms: A Test Using Freshwater Fishes , 2002, The American Naturalist.

[26]  K. G. Ashton.  Patterns of within-species body size variation of birds: strong evidence for Bergmann's rule , 2002 .

[27]  K. G. Ashton.  Do amphibians follow Bergmann's rule? , 2002 .

[28]  M. C. Tracy,et al.  Is Bergmann’s Rule Valid for Mammals? , 2000, The American Naturalist.

[29]  R. Highton,et al.  Geographic Protein Variation and Speciation in Salamanders of the Plethodon Jordani and Plethodon Glutinosus Complexes in the Southern Appalachian Mountains with the Description of Four New Species , 2000 .

[30]  L. Houck,et al.  The Biology of Plethodontid Salamanders , 2000, Springer US.

[31]  A. Palmer,et al.  Detecting Publication Bias in Meta‐analyses: A Case Study of Fluctuating Asymmetry and Sexual Selection , 1999, The American Naturalist.

[32]  N. Loder,et al.  Geographic gradients in body size: a clarification of Bergmann's rule , 1999 .

[33]  R. Highton.  GEOGRAPHIC PROTEIN VARIATION AND SPECIATION IN THE SALAMANDERS OF THE PLETHODON CINEREUS GROUP WITH THE DESCRIPTION OF TWO NEW SPECIES , 1999 .

[34]  G. Arnqvist,et al.  MetaWin: Statistical Software for Meta-Analysis with Resampling Tests. Version 1.Michael S. Rosenberg , Dean C. Adams , Jessica Gurevitch , 1998 .

[35]  Dean C. Adams,et al.  RESAMPLING TESTS FOR META‐ANALYSIS OF ECOLOGICAL DATA , 1997 .

[36]  Bryan F. J. Manly,et al.  Are there Clumps in Body-Size Distributions? , 1996 .

[37]  R. Highton.  Speciation in Eastern North American Salamanders of the Genus Plethodon , 1995 .

[38]  Jessica Gurevitch,et al.  A Meta-Analysis of Competition in Field Experiments , 1992, The American Naturalist.

[39]  P. J. Green,et al.  Density Estimation for Statistics and Data Analysis , 1987 .

[40]  J. Felsenstein.  Phylogenies and the Comparative Method , 1985, The American Naturalist.

[41]  R. Rosenthal.  Meta-analytic procedures for social research , 1984 .

[42]  D. Wake,et al.  Body Size and Elevation in Neotropical Salamanders , 1982 .

[43]  C. C. Lindsey.  BODY SIZES OF POIKILOTHERM VERTEBRATES AT DIFFERENT LATITUDES , 1966, Evolution; international journal of organic evolution.

[44]  A. Sayler.  The Reproductive Ecology of the Red-Backed Salamander, Plethodon cinereus, in Maryland , 1966 .

[45]  Carleton Ray.  The application of Bergmann's and Allen's rules to the poikilotherms , 1960 .

[46]  Ernst Mayr,et al.  GEOGRAPHICAL CHARACTER GRADIENTS AND CLIMATIC ADAPTATION , 1956 .