One major symbol in the novel is that of rain. Rain is symbolic of a ritual cleansing and new beginnings.
Another major symbol in the novel is that of rabbits, as Minerva compares herself to a rabbit is a cage. Rabbits symbolize Minerva's feeling of entrapment.
Sometimes, watching the rabbits in their pens, I’d think, I’m no different from you, poor things. One time, I opened a cage to set a half-grown doe free. I even gave her a slap to get her going.
In the Time of the Butterflies