Taxa de alimentação e taxa de crescimento de Nucella lapillus predando em Littorina obtusata e Mytilus edulis

Abstract

n the present work, the feed rate and growth rate of four populations of Nucella lapillus preying on Littorina obtusata and Mytilus edilus were studied. To test the hypothesis that the feeding rates of N. lapillus preying on M. edulis and L. obtusata are influenced by prey density, individuals of N. lapillus from the four populations were placed in separate boxes with three or five prey inside tanks with sea water. To determine which diet would enable a higher growth rate, two groups of ten juveniles from one of the four populations of N. lapillus were placed in separate boxes, one group feeding on M. edulis (10-30 mm) and the other on L obtusata (5-12 mm) for 8 months. Adults and juveniles of N. lapillus showed a higher feeding rate, preying on M. edulis and L. obtusata, in experiments with higher prey density. These results may represent a non-adaptive response to the increase in the concentration of chemosensory or tactile stimuli due to greater prey abundance or an adaptive response, since an increase in prey abundance can reduce the predation effort related to capture, competition and risks. N. lapillus showed a higher growth rate, preying on M. edulis, so that this species stands out as having greater nutritional value.