Consumer-resource body-size relationships in natural food webs.
It has been suggested that differences in body size between consumer and resource species may have important implications for interaction strengths, population dynamics, and eventually food web structure, function, and evolution. Still, the general distribution of consumer-'resource body-size ratios in real ecosystems, and whether they vary systematically among habitats or broad taxonomic groups, is poorly understood. Using a unique global database on consumer and resource body sizes, we show that the mean body-size ratios of aquatic herbivorous and detritivorous consumers are several orders of magnitude larger than those of carnivorous predators. Carnivorous predator-prey body-size ratios vary across different habitats and predator and prey types (invertebrates, ectotherm, and endotherm vertebrates). Predator-prey body-size ratios are on average significantly higher (1) in freshwater habitats than in marine or terrestrial habitats, (2) for vertebrate than for invertebrate predators, and (3) for invertebrate than for ectotherm vertebrate prey. If recent studies that relate body-size ratios to interaction strengths are general, our results suggest that mean consumer-resource interaction strengths may vary systematically across different habitat categories and consumer types.
Brose
Ulrich
U
Department of Biology, Darmstadt University of Technology, Darmstadt, Germany. brose@bio.tu-darmstadt.de
Jonsson
Tomas
T
Berlow
Eric L
EL
Warren
Philip
P
Banasek-Richter
Carolin
C
Bersier
Louis-Félix
LF
Blanchard
Julia L
JL
Brey
Thomas
T
Carpenter
Stephen R
SR
Blandenier
Marie-France Cattin
MF
Cushing
Lara
L
Dawah
Hassan Ali
HA
Dell
Tony
T
Edwards
Francois
F
Harper-Smith
Sarah
S
Jacob
Ute
U
Ledger
Mark E
ME
Martinez
Neo D
ND
Memmott
Jane
J
Mintenbeck
Katja
K
Pinnegar
John K
JK
Rall
Björn C
BC
Rayner
Thomas S
TS
Reuman
Daniel C
DC
Ruess
Liliane
L
Ulrich
Werner
W
Williams
Richard J
RJ
Woodward
Guy
G
Cohen
Joel E
JE
D000818:Animals; D049628:Body Size / Q000502:physiology*; D017753:Ecosystem; D020387:Food Chain; D005618:Fresh Water; D009792:Oceans and Seas; D011235:Predatory Behavior / Q000502:physiology