The Taylor's checkerspot butterfly (also known as the Whulge checkerspot) became a candidate species in October 2001. An annual review of the species was done in December 2007. On October 11, 2012, the USFWS announced a proposal to list the butterfly under the ESA. More information.

Historical Status

The Taylor's checkerspot is a prairie species once found throughout grasslands in the Willamette Valley, Puget Sound, and south Vancouver Island. Historic range and abundance is not precisely known because exhaustive searches did not occur until recently. Northwest grasslands were formerly more common, larger and interconnected - conditions that likely would have supported a greater distribution and abundance of Taylor's checkerspot. Before its decline, the checkerspot was documented at more than 70 sites in British Columbia, Washington, and Oregon. These sites included coastal and inland grasslands (prairies) on southern Vancouver Island and surrounding islands in British Columbia and the San Juan Island archipelago, as well as open prairies on post-glacial gravelly outwash and balds in Washington's Puget Trough and Oregon's Willamette Valley. In Oregon, there were 14 recorded sites from which this subspecies had been either collected or observed over the last century.

Current Trends

Today, the Taylor's checkerspot is extirpated (locally extinct but exists elsewhere) from British Columbia and all but one locale in the Willamette Valley. By 1989, fewer than 15 populations remained in the Pacific Northwest, and as of October 2002, there are only four confirmed populations, although it may exist at three additional locales. In Oregon, the checkerspot is found at only one site, in Benton county, on a grassy bald and powerline right-of-way area owned by the Weyerhauser Company.

Description and Life History

Taylor's checkerspot is the darkest subspecies of the Edith checkerspot. It is a medium-sized, colorfully-checkered butterfly with a wing span of 5.7 centimeters (2.25 inches). The ventral surface of the wings are primarily orange with bands of white cells. The dorsal portion of the wings has a proportionate mix of black, orange, and white. It is one of the smallest of the Edith checkerspots, and it has short and stubby wings.

Adults emerge in the spring, during April and May, when they mate and lay clusters of as many as 1,200 eggs. Larvae emerge and grow until the fourth or fifth instar. Larvae feeding on wildflowers in Puget Trough have been documented to enter diapause in mid-June to early July, hibernating through the winter.

Habitat

Habitat requirements for the Taylor's checkerspot consist of open grasslands and grass/oak woodland sites where food plants for larvae and nectar sources for adults are available. These sites include coastal and inland prairies on post-glacial, gravelly outwash and balds. Taylor’s checkerspot larvae have been documented feeding on members of the figwort or snapdragon family (Scrophulariaceae), including paintbrush (Castilleja hispida) as well as native and non-native Plantago spp. in the plantain family (Plantaginacea). The last remaining population in Oregon also depends upon P. lanceolata. Within the entire range of the Taylor’s checkerspot, prairie habitat was historically maintained, in part, through periodic burning by Native Americans.

Reasons for Decline

The major limiting factors affecting this species are related primarily to the significant loss of suitable habitat that is largely due to agricultural and urban development, encroachment of trees, and spread of invasive plants which threaten the native grasslands in which the species is found. Pesticide use and recreational activities pose a direct threat to the butterflies themselves. The impact of these threats has led to a smaller and smaller number of extant (still existing) populations, with the natural instability of small populations. Most of the remaining checkerspot habitat sites are a considerable distance from one another, likely well beyond dispersal distance. Natural re-colonization is unlikely as populations disappear.

References and Links

The Xerces Society