Alabama Butterfly Atlas

Great Southern Whites tend to be wanderers. Individuals often disperse, but the species is known for massive emigrations where thousands leave to colonize new territory. Coastal movement is common, and some years they travel inland, using a variety of weedy mustard plants for reproduction.  Jim Egbert, who documented Great Southern Whites in Alabama, observed such a mass movement in June 2016.  He reported seeing hundreds flying in south Baldwin County, and at times, was able to see three "whites" together: Cabbage, Checkered, and Great Southern. In the fall, Great Southern Whites often make a backward trek.  These butterflies cannot tolerate hard freezes in any life stage, and there is no winter diapause. Freezing temperatures leave settlements only in more tropical climates like south Florida and southern Texas. There Great Southern White pioneers wait for warm weather to reinstate their northern expansion.

Males are always white, but females vary by season.  Late season females are also white, but longer day lengths trigger some caterpillars to produce dark form (‘nigra’) females with extensive gray scaling. These are on the wing in summer months, although some white females still occur. Eggs are laid in groups on a variety of plants in the mustard family. Caterpillars are gregarious when young, but separate as they mature. They gain some chemical protection from the mustard oils they ingest, and this persists into adulthood. Great Southern Whites are less palatable to birds than many other butterflies.

Great Southern Whites have documented occurrences throughout Florida and in portions of the eastern coastal states.  They make it to Alabama during high dispersal years.