Euchloe ausonides insulana
Euchloe ausonides insulanus, the island marble butterfly, is a subspecies of the Euchloe ausonides (large marble butterfly) and is found in the San Juan Islands in Washington in the northwestern United States. The butterfly was thought to be extinct and was last observed on Gabriola Island, British Columbia in 1908. The species was rediscovered during a prairie butterfly survey in San Juan Island National Historical Park in 1998. After this rediscovery, surveys were conducted throughout the presumed range and found a few populations on San Juan Island and Lopez Island, but no remaining populations in Canada. Description The Island Marble is medium sized butterfly that is distinguishable by its white and green mottled pattern under its hind wings. Habitat The Island Marble butterfly is primarily coastal prairie dwelling species and an indicator for the health of the prairie ecosystem. This species has three known host plants which are located in different ecosystems. Brassica rapa grows primarily in the prairies, Sisymbrium altissium grows in sandy habitats, and Lepidium virginicum grows in coastal areas. Previously, the Island Marble Butterly inhabited various areas in the San Juan and Lopez islands. However, it is currently only found in the American Camp site at San