The U.S. Fish and Wildlife Service today announced it will be conducting a status review of the monarch butterfly under the Endangered Species Act (ESA). The Service has determined that a petition from the Center for Biological Diversity, the Center for Food Safety, the Xerces Society for Invertebrate Conservation and Dr. Lincoln Brower to list a subspecies of monarch (Danaus plexippus plexippus) presents substantial information indicating that listing may be warranted.