This is a story about one of the most fascinating in one of the most unlikely places. A small island in the Pacific Ocean, which has been dubbed the Méxican Galápagos, is where the action is. Welcome to The Socorro Island, where the swarming reign.

Locust Hojun Song, David B. Weissman, Ludivina Barrientos-Lozano, Island and Zenón Cano-Santana

n the Book of Exodus, a plague of locusts cov- Socorro Island—Méxican Galápagos ered the land of Egypt as one of 10 miraculous Socorro Island is the largest of four islands of the Isigns from God to warn and dishearten Pha- Islas Revillagigedo, located about 480 km south- raoh. Swarming locusts of biblical scale are still west of Baja California, México (Fig. 1). This group a source of great fear across the world; northern of Pacifi c islands is oceanic and volcanic in origin Africa is experiencing one of its worst outbreaks and is probably early Pleistocene in age (Brattstrom of the desert in the past 50 years. Close to 1990). The island chain consists of Roca Partida, home, on a remote island off the west coast of San Benedicto, Clarion, and Socorro, in increasing México, one can presently fi nd a great swarm of size. Socorro Island was discovered in 1608 by the locusts. Nature has performed an intriguing colo- Spanish captain, Martin Yañez de Armida, who nization experiment on Socorro Island, where we came in search of gold, following the tales of the witnessed some amazing aspects of locust biology. Toltecas Indians (Hanna 1926). After an unsuccess- This is a story of our journey, a closer look at the ful search, the captain realized that there was no locust island. such treasure and abandoned the journey, but he gave the island a name to honor his wife, Socorro (which also means “help” in Spanish). The fi rst scientifi c expedition to the island was Fig. 1. Map of organized and sponsored by the California Acad- Socorro Island emy of Sciences (CAS) in 1925 (Hanna 1926). (modifi ed from A group of scientists consisting of a botanist, an Richards and entomologist, a herpetologist, an ornithologist, a Brattstrom 1959). mammalogist, and two paleontologists explored the island group for about 20 d, documenting their biodiversity. Since 1925, there have been numer- ous expeditions by various groups (Richards and Brattstrom 1959, Palacios-Vargas et al. 1982). Notably, ornithologists have visited Socorro Island most frequently, in an effort to reintroduce the endemic Socorro dove, which became extinct in the wild sometime between 1958 and 1978 (Jehr and Parkes 1982). The island is also visited by whale researchers because it is a known breeding site for humpback whales. In 1957, the Méxican government established a naval station on the southeastern portion of the island (Brattstrom 1990). Currently, Socorro Island is permanently occupied only by military personnel. The Islas Revillagigedo are home to numerous

168 American Entomologist • Fall 2006 endemic species (31.7% of the vertebrate fauna is on Socorro Island, and Zenón Cano-Santana, a endemic) and have been compared with the Galá- professor at Universidad Nacional Autónoma de pagos Islands in terms of biodiversity (Brattstrom México (UNAM), became the principal investiga- 1990). The International Union for Conservation tor of this project. With the help of the Méxican of Nature and Natural Resources (IUCN) has con- Navy, seven trips to the island were taken, starting sidered the islands a priority biodiversity area since in February 2004. 1980, and the Méxican government declared the islands to be a Biosphere Reserve in 1994 (Valero Identity Revealed et al. 2005). Despite these efforts, the islands are Of the approximately 10,000 described species severely impacted by introduced exotic of () in t