Selectivity and growth of the generalist herbivore Dolabella auricularia feeding upon complementary resources

Abstract

The sea hare Dolabella auricularia (Gastropoda: Opisthobranchia: Anaspidea) grew far better upon an ad lib mixture of four species of algae than upon any of the algal species alone, suggesting that algae were complementary resources. When offered three pairs of algae in 4:1 and 1:9 ratios, Dolabella changed its foraging behavior so that the rarer alga was preferrred. Consequently, the mixtures of algae consumed where more similar between treatments (ratios) than the mixtures of algae offered. Results suggest that Dolabella actively maintains a mixed diet because it is nutritionally superior to any single diet. An alternative hypothesis (the nonadditive toxin hypothesis) was not supported. -from Authors