Changes in the feeding behavior of the deposit-feeding polychaete<Emphasis Type="Italic"> Laeonereis acuta</Emphasis> on soft sediments inhabited by burrowing crabs

In this paper, we evaluate the influence of the burrowing crab Chasmagnathus granulatus on the feeding behavior, body condition, burrowing activity, and fecal production of the deposit-feeding polychaete Laeonereis acuta. Previous results and ours show that, due to crab activity, sediment organic matter decreases with depth outside a crab bed, but there were no differences inside. Also, particle sizes were smaller inside the crab bed. Polychaetes showed better body condition inside the crab bed, suggesting higher energy gain. They fed on the surface more frequently outside the crab bed than inside. However, feeding rate was higher inside the crab bed, which is consistent with the larger weight and volume of fecal pellets found inside crab bed. In both areas, the bedload sediment transport was not similar to the sediment ingested by this polychaete. A 1-month exclusion/inclusion experiment performed outside and inside the crab bed showed that the body condition of polychaetes changed between areas but that this was not directly due to crab manipulation. Thus, our results suggest that the higher sediment quality inside a crab bed can positively affect the feeding behavior of the deposit-feeding polychaete L. acuta, increasing its feeding rate and consequently enhancing its body condition.Communicated by P.W. Sammarco, Chauvin