These caterpillars are the larvae of the Monarch butterfly. Female Monarch butterflies lay their eggs on plants that are in the milkweed family. When the eggs hatch, small caterpillars come out. As they feed on the milkweed plant the caterpillars grow larger, often as long as 2 inches. When the caterpillars are finished feeding they usually will move off of the plant to form a chrysalis. While in the chrysalis stage they are transforming into their adult stage. Adult butterflies will emerge after about 5 to 7 days.

The caterpillars may eat all of the leaves from your milkweed plant, but new ones will grow in their place.

Additional Resources

http://edis.ifas.ufl.edu/IN780

www.floridata.com/tracks/butterfly/lifeCycle.cfm

http:// edis.ifas.ufl.edu/pdffiles/IN/IN56400.pdf