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Recently, research into the trophic structure of ecological networks has
undergone a dramatic renaissance, with new research avenues opening up
and some of the earliest ecological ideas being revisited with new data and
theories ( Ings et al., 2009 ). This is in part due to the development of ''network
science'' as a discipline whose ideas have found a natural home in the
complex world of ecology, but also largely due to the new availability of
well-resolved and far more exhaustively sampled datasets ( Dunne, 2006 ).
One particularly important finding that has emerged from these investiga-
tions has been that the trophic structure of a community appears to be largely
explicable with reference to only a single dimensional niche space
( Cohen,1978; Cohen and Newman, 1985; Stouffer et al., 2005, 2006;
Williams and Martinez, 2000 ). That is to say, it is possible to order prey
species in such a way that the diets of predators can be represented as
contiguous segments over that ordering. It was not long before a connection
was made between a species position in the hierarchy of this single dimension
and its body size ( Lawton, 1989; Neubert et al., 2000; Stouffer et al., 2011;
Warren and Lawton, 1987; Williams et al., 2010; Woodward et al., 2005a,b;
Zook et al., 2011 ).
This growing recognition of the importance of body size for structuring
food webs has led to numerous studies examining the existence of regularities
in trophic relations with the body sizes of species involved ( Woodward et al.,
2005b,c; Yvon-Durocher et al., 2011 ). For instance, some studies have com-
piled interactions from across many food webs to explore relationships
between predator and prey size ( Brose et al., 2006a; Cohen et al., 1993;
Gittleman, 1985 ; Riede et al., 2011; Vezina, 1985 ), while others have exam-
ined patterns within a single, local food web ( Cohen, 2007; Cohen et al.,
2003; de Visser et al., 2011; Jacob et al., 2011; Leaper and Huxham, 2002;
McLaughlin et al., 2010; Memmott et al., 2000; O'Gorman and Emmerson,
2010; Warren and Lawton, 1987; Yvon-Durocher et al., 2008 ). The way in
which the range of prey sizes a predator consumes changes with the preda-
tor's size has also been explored, especially in aquatic systems where gape-
limited predation is prevalent ( Leaper and Huxham, 2002; Sinclair et al.,
2003; Warren and Lawton, 1987; Woodward and Hildrew, 2002; Woodward
et al., 2010 ). These studies have often revealed strong body-size constraints
on trophic interactions, with larger predators feeding over a larger range of
prey sizes, although sometimes at the local level the relationships weaken or
vanish (e.g. Leaper and Huxham, 2002 ).
Similarly, studies have also explored how network measures such as gen-
erality (the number of prey of a species), vulnerability (the number of
predators of a species), and trophic height (TH) (the trophic position of a
species within a food web considering its direct and indirect prey) scale with
species average mass, both within and across food webs. Generality and TH
tend to scale positively, whereas vulnerability tends to scale negatively
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