Energy maximization by selective feeding on tissues of the venerid clam Marcia hiantina in the marine scavenger Nassarius festivus (Gastropoda: Nassariidae)

Abstract

Feeding selectivity of the intertidal scavenging gastropod Nassarius festivus on four types of tissue (soft tissue, adductor muscle, foot, mantle margin) of the venerid clam Marcia hiantina was studied by field observations and laboratory experiments. Both approaches showed similar results with the soft tissue and adductor muscle being much preferred. As the energy content of the four types of tissue was similar and individuals of N. festivus rearing in different types of tissue obtained similar growth rates both in shell length and in body wet weight, differential consumption was most likely determined by the palatability of the tissues. Energy intake in a meal for N. festivus was estimated at 10.92, 9.17, 3.86 and 2.02 cal meal−1 ind−1 for soft tissue, adductor muscle, mantle margin, and foot, respectively. In view of the small size and sporadic distribution of the carrion, and intense competition among the conspecifics, selective feeding on more palatable tissues maximizes energy intake for scavengers like N. festivus.