Apodemia mormo langei Comstock, 1939
Date of listing: 1976
Federal Status: Endangered
State Status: None
Lange’s Metalmark is known almost exclusively from what is now the Antioch Dunes National Wildlife Refuge, established largely for the butterfly’s protection in 1980. The butterfly’s numbers began to decline early in the century as the growth of San Francisco led to the dunes being mined heavily for sand.
This butterfly, like most others, has a close relationship with the food plant of its larvae, in this case naked-stemmed buckwheat (Eriogonum nudum). Adults emerge in late summer. They live for approximately one week during which time they feed, mate, and locate the host buckwheat on which to deposit the eggs. The eggs are dormant for several weeks. Then, as the fall rains begin and new growth of Eriogonum appears, the eggs hatch and the tiny larvae begin to feed. Feeding continues through the winter and spring with pupation occurring in the next summer.
The Antioch Dunes have faced mining, construction, agriculture and trampling by unknowing recreationists. But, ultimately, one of the biggest problems faced by Lange’s metalmark is a fundamental change in the dune structure. Formerly a dynamic mosaic of open sand and vegetation, the dunes have slowly been stabilized by the removal of sand and by the introduction of plants which have spread over the sand and now prevent much sand movement. Under these conditions, the host Eriogonum does not reproduce well. Its seedlings require open sand to become established. The realization that disturbance was important in the maintenance of the dunes was critical. Now through intentional disturbance, efforts at encouraging the host plant have proven much more fruitful. The butterfly’s numbers are on the rise, from fewer than 200 individuals in 1986 to several thousand in recent years. With much of the area already a preserve, and with the cooperation of PG & E on whose land the species also relies, the prognosis for Lange’s Metalmark is relatively good.
For further reading:
Arnold, R.A., 1983. Ecological studies of six endangered butterflies (Lepidoptera: Lycaenidae): Island biogeography, patch dynamics, and design of habitat preserves. University of California Publications in Entomology 99: 1-161.
Howard, A.Q. and R.A. Arnold, 1980. The Antioch dunes – safe at last? Fremontia 8: 3-12.
Opler, P.A. and L. Robinson, 1986. Lange’s Metalmark butterfly. In: Audobon Wildlife Report. New York, National Audubon Society.
Powell, J.A., 1978. Endangered habitats for insects: California coastal sand dunes. Atala 6(1-2): 41-55.