Proximate and Functional Causes of Polyphenism in an Anuran Tadpole

Abstract

Few systems have been explored in sufficient detail to link the proximate causes of polyphenism to the ecological factors that favour discontinuous, environmentally induced variation. I examined the developmental and physiological bases underlying polyphenism in southern spadefoot toad tadpoles (Scaphiopus multiplicatus). Scaphiopus often occurs as two discrete trophic morphs : carnivores and omnivores. Carnivores develop from omnivores if the latter are fed macroscopic prey (anostracan shrimp and tadpoles). I found that tadpoles can change to the alternative morphology if their diet was switched