Energetic equivalence in a soil arthropod community from an aspen–conifer forest

SummaryWe evaluated the energetic equivalence rule for a community of litter and soil arthropods from an aspen–conifer forest in the Sangre de Cristo Mountains of southwestern North America. We found that across taxa and within trophic groups the number of arthropods per square meter, N, scaled with body mass, M, raised to the −0.78 power and that primary and secondary decomposers, combined, were 8.51 times more abundant than carnivores. Given that arthropod abundance scaled as M−0.78 and that soil invertebrate metabolic rates, Q, scale approximately as M0.78, it appears that within coarse trophic groups at our study site, energy use by soil arthropod populations, Qtot∝NQ, is approximately independent of body size, Qtot∝M−0.78M0.78∝M0.