The Regal Fritillary butterfly (Speyeria idalia) is native to the Chicago area and depends on native tallgrass prairie plant communities. Its caterpillars feed exclusively on violet (Viola spp.), the state flower of Illinois. The restricted habitat requirements and strict food preferences make it particularly vulnerable to habitat destruction. Specimens of this butterfly and others like it housed at the Field Museum help scientists answer questions about its evolution and changes in distribution over time.