Ecological energetics of populations of four sympatric isopods in a Hong Kong forest

Abstract

Population energy budgets of Burmoniscus ocellatus, Burmoniscus sp. (Philosciidae), Formosillo raffaelei and Orodillo maculatus (Armadillidae), were calculated. Mean population standing stock of the four species ranged from 1.25-13.61 kJ m -2. Mean total isopod biomass at the two sites was 0.85 and 1.85 g m -2. Annual production of the four species varied from 4.24-30.43 kJ m -2 with 5.2-26.4% (energy content) allocated to reproduction. Annual production of the four species combined at the two sites was 23.22 and 50.15 kJ m -2. P/<> -\B ratios varied from 2.24-4.27. Annual population consumption on mixed litter by the four isopod species ranged from 28.4-183.0 kJ m -2. Total annual consumption by all species at the two sites was 233.7 and 360.2 kJ m -2 (1.96 and 2.53% of annual litter fall). Isopod respiratory rates were proportional to body weight, with an exponent ranging from 0.68-0.78 at 23°C. The annual population metabolism of the four species varied from 14.62-86.11 kJ m -2. Total annual isopod metabolism at the two sites was 116.33 and 185.95 kJ m -2. -from Authors