Incisalia polia maritima
This insect is a subspecies of the hoary elfin butterfly and is found only in very limited areas of the Oregon and Washington coasts. The butterfly has a mottled gray-brown body with some sienna or orange visible on the underside of the wings. The name derives from the white “frosting” coloration on the outer edge of the forewing (“hoary” means frosted).
The maritima subspecies has not been widely studied but is a prime example of a specialist species. The butterfly spends its entire life in close proximity to kinnikinnick, using this host plant to lay its eggs, as a food source, and as shelter during the winter months.
The seaside hoary elfin is the second imperiled butterfly species on the Oregon coast. The other is the silverspot butterfly which is listed as threatened.
The hoary elfin butterfly can be found in limited locations throughout North America. The maritima subspecies is found only in the coastal areas of Oregon and Washington. In Oregon there are known but very limited populations in the Pistol River, Driftwood Beach and Waldport areas. It is always found close to kinnikinnick and may die off if this hostplant disappears from an area.
The seaside hoary elfin butterfly subspecies is considered critically endangered in Oregon. The major cause of its decline is thought to be invasive species such as European beach grass pushing out the kinnikinnick host plant. However, local populations can and have been destroyed by either large-scale storms or cataclysms such as tsunami. Its conservation status is largely unknown in both Washington and California. Other hoary elfin subspecies, such as those in the eastern United States and around the Great Lakes, are considered common.
Related Features: Saving the Silverspot
Photo credit: Oregon Department of Fish and Wildlife.