CHAPTER SIX
Body size and predatory interactions
in freshwaters: scaling from individuals
to communities
GUY WOODWARD
Queen Mary, University of London
PHILIP WARREN
University of SheffieldIntroduction
Body size is an attribute of individual organisms. It affects, or at least is cor-
related with, a considerable array of physical, physiological and behavioural
characteristics that determine where individuals occur and what they do
(Elton,1927; Peters,1983; Brownet al., 2004; Woodward, Speirs & Hildrew,
2005c). Such ubiquity makes body size an obvious candidate source of general
rules that can be derived from selective processes acting on individuals, but
which can also be applied at higher levels of ecological organization (Cousins,
1980 ; Peters,1983; Dickie, Kerr & Boudreau,1987; Yodzis & Innes,1992; Cohen
et al., 1993; Gaston & Blackburn, 2000 ; Cohen, Jonsson & Carpenter, 2003 ;
Emmerson & Raffaelli,2004). Although body size was identified as a key link
between natural history aspects of population dynamics and community struc-
ture many decades ago (e.g. Hardy,1924; Elton,1927; Hutchinson, 1959 ), these
early ideas have languished somewhat until relatively recently. In the last two to
three decades a plethora of allometric body-size scaling relationships have been
described and used to derive mechanisms to explain, or parameters to model,
general patterns in natural systems (e.g. Peters,1983). Recently, it has been
suggested that basal metabolic rate is the fundamental constraint that under-
pins many of the size-related patterns and processes observed in natural sys-
tems, and that a metabolic theory of ecology could, eventually, attain similar
importance to that of the genetic theory of evolutionary biology (Brownet al.,
2004 ; Brown, Allen & Gillooly, this volume). One effect of size taking a more
central place in ecological thinking is that it provides a means of integrating
approaches based on biomass and energy flux with those based on abundances
and populations (e.g. de Ruiter, Neutel & Moore,1995; Reuman & Cohen,2005;
Woodward et al., 2005a–c).
Within terrestrial ecology, the role of body size has been explored extensively
at very large spatial scales, particularly in response to latitudinal gradients
Body Size: The Structure and Function of Aquatic Ecosystems, eds. Alan G. Hildrew, David G. Raffaelli and Ronni
Edmonds-Brown. Published by Cambridge University Press.#British Ecological Society 2007.