The island marble butterfly (euchloe ausonides insulanus) is a subspecies of the large marble butterfly (E.ausonides)

This Cooperative Agreement award from the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Recovery Implementation program (CFDA 15.657) supports the development and implementation of a sustainable captive rearing program for the endangered Island Marble Butterfly. The $150,000 award will enable Woodland Park Zoo, the primary awardee, to conduct a captive rearing partner workshop in 2024 and establish a long-term captive rearing program to produce approximately 125 releasable adult butterflies annually. This effort aims to augment the remaining wild population of 200-500 Island Marble Butterflies on San Juan Island, Washington and prepare for future recovery actions to reestablish the species across its historic range. The project addresses the critical need to shift from labor-intensive annual captive rearing to a more sustainable approach to prevent the extinction of this endangered subspecies.

IT was historically known from vancouver island, canada, and was not observed between 1908 and 1998 when IT was rediscovered on SAN juan island, washington, united states. On april 12, 2018, the US fish and wildlife service (USFWS) published a proposed rule in the federal register (FR 83 FR 15900) to list the island marble butterfly (IMB) as an endangered species and to designate critical habitat. The current population of 200-500 butterflies is reliant on local captive rearing efforts to ensure that a subsetof wild eggs laid in one season survive to emerge as breeding adults the following season. Island marblebutterflies are collected by biologists from the wild in their EGG and caterpillar life stages, reared in humancare in a lab for pupation and overwintering, and then released as breeding adults the following spring. Thecaptive rearing efforts have been successful at producing a limited number of individuals to augment thepopulation at SAN juan island national historical park (SJINHP) to prevent extinction driven by predation, hostplant habitat loss, and climate change. However, IT has been an annual, labor-intensive process with limitedoutput due to a variety of reasons, and the program requires a shift to a more sustainable approach to supportrearing efforts and prevent IMB extinction. In the short-term, island marble butterfly recovery hinges on supporting the single-known population throughcaptive rearing and on future production of butterflies and suitable habitat at a scale that reestablishespopulations across the species historic range. A shift from annual efforts to a sustainable, long-term captiverearing program is a need identified by IMB partners to support the recovery of this butterfly. The perilous status of the endangered island marble butterfly, the need to transition from annual efforts to asustainable captive rearing program, and the opportunity to partner with expert capacity of woodland park zoostaff are the focus of this inflation reduction act project to recover the island marble butterfly. This project with woodland park ZOO includes the development and implementation of:a captive rearing partner workshop in 2024.a sustainable captive rearing program for island marble butterfly.activities to captively rear cohorts of island marble butterflies ( 125 annually) for release in support ofrecovery activities. The USFWS anticipates that this project will result in the development of a sustainable captive rearing programfor island marble butterflies, with multiple cohorts of releasable adult butterflies to augment the population onsan juan island and activities to prepare the partners and program for additional recovery actions to supportthis endangered species.