Extraoral and intraoral feeding: flexible foraging tactics in the South American sun‐star, Heliaster helianthus

The South American sun‐star, Heliaster helianthus, is capable of adopting both the extraoral and intraoral mode of feeding. Observations were made on the feeding activities of H. helianthus in an intertidal habitat in central Peru. The proportion of individuals engaged in intraoral feeding was high amongst small H. heliunthus of less than 14 cm in diameter and gradually declined in larger size classes. Extraoral feeders had significantly larger meal sizes (total prey biomass) than intraoral feeders in all the size categories of H. heliunthus. Extraoral feeders also consumed larger individuals of the most important prey species, Semimytilus algosus, than intraoral feeders. The advantages and disadvantages of the two feeding modes are discussed and the meaning of the dual foraging tactics in H. helianthus is considered.