Figure 1.
Ontogenetic shifts of respiration–mass exponents (bR) in relation to mass–length exponents (bL) of several species of aquatic invertebrates in five different phyla (a) and for all species averaged together (b,c), where bR is the scaling exponent for log10 RMR in relation to log10 body mass, and bL is the scaling exponent for log10 body mass in relation to log10 total body length (data from tables 1 and 2). Multiple b values for the life-history stage of a species or group of species (copepods) were averaged. Arrows indicate the direction of ontogenetic change. In (b,c), the upper left and lower right points were calculated by averaging all of the paired bR and bL values that occurred in ontogenetic stages with the higher versus lower bR, respectively. The 95% confidence limits are shown for each mean value of bR and bL.. Also shown in (b) are the bounded range of values of bA (log10 body SA in relation to log10 body mass) in relation to bL (depicted as light purple lines) calculated using equations (3.1) and (3.2) based on Euclidean geometry (also see [8]); and in (c) the predicted effects of body-shape changes (bL) on bR (depicted as dashed coloured lines) according to the RTN models of West et al. [16], Banavar et al. [2] and Dodds [17] (also see [8]). Note that in seven of eight species sampled, ontogenetic shifts in bL are accompanied by inverse shifts in bR, as predicted by SA scaling theory (b), but in contradiction to RTN scaling theory (c). (Online version in colour.)