Abundance, Body Size and Biomass of Arthropods in Tropical Forest

Samples representing 32 624 arthropods were collected using standard sampling methods from five habitats in lowland rain forest (canopy, tree trunks, low herb layer, leaf litter and soil) in Seram, Indonesia. The relationships between arthropod abundance (number of individuals), body size, and biomass are described for these five habitats, for the predicted arthropod fauna of a hectare of forest, and for different trophic groups. The results are similar for all five habitats; abundance decreases and biomass increases with body size. Broadly similar principles apply for herbivores, decomposers and predators but not for «tourists». Thus the «equal biomass hypothesis», which predicts roughly constant biomass across logarithmic size classes, is rejected