It takes about 12-16 days for the monarch to complete the pupae stage and emerge as an adult monarch butterfly. Depending on the weather, they may overwinter in this stage, or they could complete their lifecycle and migrate to Florida or Mexico. To learn about monarch migration in Georgia see this link.
To give you an idea of how much food a SINGLE monarch caterpillar needs, here are before and after pictures of 1 milkweed plant that had 1 caterplillar:
Previous monarch posts:
http://katalystdesigns.blogspot.com/2007/04/first-of-season.html
http://katalystdesigns.blogspot.com/2007/06/monarch-caterpillars.html
http://katalystdesigns.blogspot.com/2007/08/more-monarchs.html
http://katalystdesigns.blogspot.com/2007/09/last-of-season.html
