Back   Did you know? One monarch butterfly can lay hundreds of eggs. When those eggs become adults, each female can lay hundreds more eggs. And when those monarch become adults each female can lay hundreds more eggs, and so on. Today, find out how quickly a billion butterflies could be born. (And explore why don't we have a billion monarch butterflies!) Female monarch laying egg on common milkweed (Asclepias syriaca). Monarchs lay one egg at at time. When milkweed is plentiful they typically lay only one egg per milkweed plant (or stalk).