Prey-species selection by the anemone predator Aeolidia papillosa (L.): The influence of ingestive conditioning and previous dietary history, and a test for switching behaviour

The nudibranch mollusc Aeolidia papillosa (L.) is known to prey on a wide variety of anemone species and has previously been shown to exhibit "ingestive conditioning"; i.e. nudibranchs show a significant preference for the anemone species upon which they have recently been feeding. In this paper the laboratory analysis of "ingestive conditioning" has been extended, using a multiple choice-chamber apparatus, to investigate the effects of both present conditioning diet and past history of diet, for N.W. European (U.K.) and for N.W. American (U.S.A.) Aeolidia. The hypothesis that not only current conditioning diet, but also past history of diet, influenced the prey-preferences of individual nudibranchs was upheld for Aeolidia from both geographic localities. It had been previously suggested that ingestive conditioning may provide a mechanism whereby switching behaviour is effected. A series of experiments to test for such behaviour have been conducted for Aeolidia using two anemone species, Sagartia troglodytes (Price) and the red morph of Actinia equina (L.), which are both known to exert a strong conditioning effect. The hypothesis that "ingestive conditioning" would result in switching behaviour could not, however, be upheld. In most cases nudibranchs demonstrated a preference for Sagartia troglodytes. It is concluded that, in the habitat upon which these experiments were modelled, Aeolidia does not exhibit switching behaviour.