Island Marble butterflies (known as Euchloe ausonides insulanus to you scientific types) are a fascinating subspecies of Large Marble Butterflies. Scientists believe they have been around for 200 million years - before their main food source, flowers, even existed! The Island Marble was thought to have gone extinct but was rediscovered in 1998 at American Camp on San Juan Island. Originally, the Island Marble’s range was comprised of southern Vancouver Island, BC and some of the Canadian Gulf Islands. It was never spotted in the San Juans until its rediscovery in 1998. Now it is only found on a few acres of San Juan Island.
The Island Marble exists in limited numbers and within a small region, so it is currently being considered for protection under the Endangered Species Act. Because this species has existed for so long, scientists believe it could provide insights on adapting to drastic environmental changes. Hopefully its proven ability to adapt will help it overcome the threats it faces today.
Wild mustards, both native and non-native, are the main food source for Island Marble caterpillars. Unfortunately, these plants are also a favorite food for deer, rabbits, and snails that gobble up the helpless Island Marble eggs and caterpillars along with the mustards. Other threats to the species include the destruction of host plants due to agriculture, rising tide levels, and other human interferences.
There are a few ways that you can help the Island Marble. First, don’t capture or collect these butterflies, it’s against the law! Second, if you live in the region, plant native flowers to feed them and other pollinators. Third, stay informed and spread the word about this at-risk animal. With your help we just might be able to appreciate these resilient butterflies for generations to come.