Consumer-resource body-size relationships in natural food webs

Department of Biology, Darmstadt University of Technology, Darmstadt, 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


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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    • "Many studies have demonstrated body size–trophic level linkages (e.g. Cohen et al. 2003; Thierry et al. 2011), and in particular that, in general, increases in prey body size enhance the ability of predators to capture prey (Woodward et al. 2005; Brose et al. 2006). In the Scioto River system, larger-bodied aquatic insects feeding at least in part on benthic algae are likely to be contributing to spider nutrition. "
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    Marine and Freshwater Research 07/2015; · 1.47 Impact Factor
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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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    ABSTRACT: Simple morphological traits of phytoplankton have proven to correlate well with the functional properties of taxa. A logical way of distinguishing functional groups of phytoplankton is to cluster species according to their morphological traits, instead of phytosociological traits, which are difficult to measure and incomplete for the vast majority of phytoplankton species. This novel approach inspired the establishment of morphologically based functional groups (MBFG) for lake phytoplankton. This study considers the MBFG as a potentially suitable tool for investigating and comparing the potamoplankton assemblages in riverine ecosystems. This study constructed a special version of MBFG that is aimed at rivers, termed MBFGR. MBFGR is based on information obtained from more than 800 samples of potamoplankton and zooplankton collected from 101 rivers located in four climate zones. Their habitat templates were also described by the thresholds of the environmental variables that promote group dominance. Despite its similar framework with MBFG, MBFGR emphasized the presence of flagella, size and shape, exoskeletal structures, life strategy and subdivision of diatoms. Their habitat templates are outlined by additional factors connected to hydrology and river types. Moreover, each discussed template includes consideration of grazing by zooplankton. Theoretically, MBFGR is better than MBFG because it can sensitively capture the ecological preferences of phytoplankton groups most associated with rivers and provides empirical values to reflect the environmental conditions in riverine ecosystems.
    Journal of limnology 04/2015; DOI:10.4081/jlimnol.2015.1173 · 1.18 Impact Factor
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    • "An important step is to link the size of the predator with the size of the consumer and the resource via an additional power law function describing prey size selection (table 1). This is accomplished by recognizing that predators consume individuals within a certain size class (Brose et al. 2006; Barnes et al. 2010; Riede et al. 2011; DeLong and Vasseur 2012a, 2012b), which means that the body size of the basal resource can be modeled as a function of the consumer's body size. Here, we do this with a power function: . "
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