they then pass them through the chrysalis stage to the adult and
even to the eggs of the next generation. The incorporation
of cardiac glycosides thus protects all stages of the monarch
life cycle from predators. A bird that eats a monarch butterfly
quickly regurgitates it (figure 25.9) and in the future
avoids the conspicuous orange-and-black pattern that characterizes
the adult monarch. Some birds, however, appear
to have acquired the ability to tolerate the protective chemicals.
These birds eat the monarchs.