Activity alters how temperature influences intraspecific metabolic scaling: testing the metabolic-level boundaries hypothesis.

A common belief is that the body-mass scaling of metabolic rate is the result of intrinsic (physical) constraints related to body design. However, many recent studies have shown that extrinsic (ecological) factors significantly affect metabolic scaling relationships, both within and among species. One of these factors is ambient temperature (T), but its influence on the intraspecific (ontogenetic) scaling slope (b) of metabolic rate varies widely.

A Perspective on Body Size and Abundance Relationships across Ecological Communities.

Recently, several studies have reported relationships between the abundance of organisms in an ecological community and their mean body size (called cross-community scaling relationships: CCSRs) that can be described by simple power functions. A primary focus of these studies has been on the scaling exponent (slope) and whether it approximates -3/4, as predicted by Damuth's rule and the metabolic theory in ecology. However, some CCSR studies have reported scaling exponents significantly different from the theoretical value of -3/4.

Activity affects intraspecific body-size scaling of metabolic rate in ectothermic animals.

Metabolic rate is commonly thought to scale with body mass (M) to the 3/4 power. However, the metabolic scaling exponent (b) may vary with activity state, as has been shown chiefly for interspecific relationships. Here I use a meta-analysis of literature data to test whether b changes with activity level within species of ectothermic animals.