Lange's Metalmark

A subspecies of the Mormon metalmark residing in the San Francisco Bay Area.

WSU Vancouver

June 10, 2022

Geography

Range Map

Lange's metalmark (Apodemia mormo langei) is endemic to the Antioch Dunes near San Francisco, California.

The Antioch dunes are a unique geologic feature for the area and are a natural hotspot for biodiversity. Now, Lange's metalmark resides only at the Antioch Dunes National Wildlife Refuge .

Antioch Dunes

Historical estimates mark the size of the dunes to be 120-500 acres within a 6,800-8,400 acre region characterized by sandy soils.

Land use changes after European colonization have led to the loss of much of the Antioch Dunes. The land changes and introduction of non-native species have led to the near elimination of the wind-blown disturbance to the habitat.

Natural History

Species interactions

Host Plant

Naked buckwheat (Eriogonum nudum var. psychicola) is the host plant for this butterfly.

Nectar Plants

The butterflies rely heavily on their host plant for nectar, which may not produce adequate quantities of nectar until the plant is three years old.

Habitat

Habitat for Lange's metalmark is exclusively stablilzed sand dune systems.

Population Dynamics

Lange's metalmark is a subspecies of Mormon metalmark, but it is isolated from all other populations of the species. The butterfly exists in one population, and its sand dune habitat is not present elsewhere on the landscape. The butterfly is likely highly sedentary relative to other metalmarks due to the hostile landscape. The highest number of butterflies seen on a single day has been below 50 every year since 2009.

Life Cycle

Adults

Adults emerge in August and fly through September. They have one brood each year (univoltine).

Eggs

Eggs are laid singly on leaves. Eggs do not hatch until the fall rain begins.

Caterpillars

They overwinters as freshly hatched caterpillars, and begin eating the host plant in the spring. They form silk and leaf nests, like this caterpillar from another mornmon metalmark.

Mormon Metalmarks

Overwintering stage may be flexible between egg and first instar caterpillars. California subspecies appear to hatch during the fall/winter, whereas in Washington eggs did not hatch until spring.

Conservation

Listing Status

Lange's metalmark was listed as Endangered under the Endangered Species Act in 1976.

Recovery Efforts

Habitat Management

Native plant restoration at the National Wildlife Refuge is a large component of restoring habitat.

In 2007, a captive breeding program began, but the metalmarks did not breed in captivity at high rates. So, the conservation team shifted to head-starting caterpillars.

Population Trends

We analyzed the data from the Lange's metalmark site prior to the start of captive rear and release. We saw the no change in abundance, and delay in phenology.