Red-cheeked salamanders are partially protected from predators because of cardiac glycosides they produce from glands on their back. when ingested, cardiac glycosides disrupt normal heart rhythms. a different salamander species, the imitator salamander, also has red cheek patches, but does not produce cardiac glycosides. it does gain protection from predators that have learned to avoid red cheeked salamanders. how does this relationship affect the population dynamics of both species?