Effects of crowding on the energetics of the barnacle Balanus glandula Darwin

Five experimental populations of the barnacle Balanus glandula Darwin, differing in their degree of crowding, were established on settling plates. Energy budgets were constructed and compared for individuals from each of the five populations. The results showed that crowding significantly reduced the energy consumption, assimilation, and production of body tissue, eggs, and shell of individual barnacles. The energy standing crop of the various body components was also reduced by crowding. Among these parameters, production of eggs appeared to be most sensitive to crowding. However, energy consumption, energy flow, and production of body tissue, eggs, and shell per unit area were all much higher in the crowded population, and the same pattern was observed for the energy standing crops of the various body components.