TY - JOUR
T1 - One size does not fit all
T2 - No evidence for an optimal body size on islands
AU - Raia, Pasquale
AU - Carotenuto, Francesco
AU - Meiri, Shai
PY - 2010/7
Y1 - 2010/7
N2 - Aim: Optimal body size theories predict that large clades have a single, optimal, body size that serves as an evolutionary attractor, with the full body size spectrum of a clade resulting from interspecific competition. Because interspecific competition is believed to be reduced on islands, such theories predict that insular animals should be closer to the optimal size than mainland animals. We test the resulting prediction that insular clade members should therefore have narrower body size ranges than their mainland relatives. Location: World-wide. Methods: We used body sizes and a phylogenetic tree of 4004 mammal species, including more than 200 species that went extinct since the last ice age. We tested, in a phylogenetically explicit framework, whether insular taxa converge on an optimal size and whether insular clades have narrow size ranges. Results: We found no support for any of the predictions of the optimal size theory. No specific size serves as an evolutionary attractor. We did find consistent evidence that large (> 10 kg) mammals grow smaller on islands. Smaller species, however, show no consistent tendency to either dwarf or grow larger on islands. Size ranges of insular taxa are not narrower than expected by chance given the number of species in their clades, nor are they narrower than the size ranges of their mainland sister clades - despite insular clade members showing strong phylogenetic clustering. Main conclusions: The concept of a single optimal body size is not supported by the data that were thought most likely to show it. We reject the notion that inclusive clades evolve towards a body-plan-specific optimum.
AB - Aim: Optimal body size theories predict that large clades have a single, optimal, body size that serves as an evolutionary attractor, with the full body size spectrum of a clade resulting from interspecific competition. Because interspecific competition is believed to be reduced on islands, such theories predict that insular animals should be closer to the optimal size than mainland animals. We test the resulting prediction that insular clade members should therefore have narrower body size ranges than their mainland relatives. Location: World-wide. Methods: We used body sizes and a phylogenetic tree of 4004 mammal species, including more than 200 species that went extinct since the last ice age. We tested, in a phylogenetically explicit framework, whether insular taxa converge on an optimal size and whether insular clades have narrow size ranges. Results: We found no support for any of the predictions of the optimal size theory. No specific size serves as an evolutionary attractor. We did find consistent evidence that large (> 10 kg) mammals grow smaller on islands. Smaller species, however, show no consistent tendency to either dwarf or grow larger on islands. Size ranges of insular taxa are not narrower than expected by chance given the number of species in their clades, nor are they narrower than the size ranges of their mainland sister clades - despite insular clade members showing strong phylogenetic clustering. Main conclusions: The concept of a single optimal body size is not supported by the data that were thought most likely to show it. We reject the notion that inclusive clades evolve towards a body-plan-specific optimum.
KW - Body size evolution
KW - Brownian motion model
KW - Island rule
KW - Mammalian phylogenetic tree
KW - Optimal body size theory
KW - Phylogenetic dispersion
UR - http://www.scopus.com/inward/record.url?scp=77954804325&partnerID=8YFLogxK
U2 - 10.1111/j.1466-8238.2010.00531.x
DO - 10.1111/j.1466-8238.2010.00531.x
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AN - SCOPUS:77954804325
SN - 1466-822X
VL - 19
SP - 475
EP - 484
JO - Global Ecology and Biogeography
JF - Global Ecology and Biogeography
IS - 4
ER -