Article

Brose, U. et al. Consumer-resource body-size relationships in natural food webs. Ecology 87, 2411-2417

Institute of Law and Social Sciences, Hohenheim University, Stuttgart, Baden-Württemberg, Germany
Ecology (Impact Factor: 4.66). 11/2006; 87(10):2411-2417. DOI: 10.1890/0012-9658(2006)87[2411:CBRINF]2.0.CO;2
Source: PubMed

ABSTRACT

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.

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    • "If the prey is small enough to be consumed by the primary predator, secondary predation by birds is a possibility , but if the prey is found to be too large to have been consumed by the primary predator, secondary predation can be ruled out. The rationale of this approach is that consumers are usually larger than their prey species (Brose et al. 2006). So if one can estimate the size of the prey species found in a bird's gut sample, the predator–prey size ratios can be calculated. "

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    • "However, the presence of flagella increased the maximum linear dimension of Group RIb, thereby allowing the species from this group to escape from small invertebrate predators with strict limitations on prey size and shape (Do and On, 1974); the presence of flagella greatly amplified the effect of water viscosity and flow ability on phytoplankton movement, thereby making it difficult for small zooplankton individuals bite or drag (Boukal, 2014). Although predators generally select size-matched prey (Brose et al., 2006), Group RIb species with small sizes were available for large zooplankton (Tab. 5), and the risk is especially high when species from this group are abundant (Van Donk et al., 2011). "
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