Selectivity and Growth of the Generalist Herbivore Dolabella Auricularia Feeding Upon Complementary Resources

• DOI: 10.2307/1940813
• Publication Date: 2006-05-09T15:13:26Z
• Authors: Steven C. Pennings; Masatomo T. Nadeau; Valerie J. Paul
• Keywords: Opisthobranchia

An assumption of most optimal diet theory is that different resources are substitutable, is, they identical in all relevant aspects and so can be ranked value using a single currency, such as energy. However, this probably not valid many cases. The sea hare Dolabella auricularia (Gastropoda: Opisthobranchia: Anaspidea) grew far better upon an ad libitum mixture four species algae than any the algal alone, suggesting were complementary resources. When offered three pairs 4:1 1:9 ratios, changed its foraging behavior rarer alga was preferred. Consequently, mixtures consumed more similar between treatments (ratios) offered. Replicate maintained on six diets for 6—7 d then maintenance another at equal abundances. Preference always higher when it compared to was. These results suggest actively maintains mixed because nutritionally superior diet. alternative hypothesis (the nonadditive toxin hypothesis) suggests herbivores might consume plant secondary metabolites less toxic one metabolite alone; consequently, total biomass hares fed single— mixed—species did single—species diets, animals those even held constant. If complementary, suggested here, several important implications follow: (1) consumers will rank absolute way each depend what else consumed, (2) consumer specialization opposed by benefits diet, (3) tend destabilize resource community, disproportionately consumed.