Great southern white butterflies (Ascia monuste) were abundant on our walk at Pelican Island National Wildlife Refuge on 4/27/2014. Karen Schuster sent this photo of one sipping nectar from lantana (Lantana camara), an invasive pest plant that is very attractive to butterflies. Two species of lantana are native to Florida, and some of the more than 200 cultivars are sterile, so, if you must have lantana in your landscape, please choose carefully.
For a larval host plant, this butterfly uses both saltwort (Batis maritima) and peppergrass (Lepidium virginicum) pictured below in a another photo from Karen …