Lange’s Metalmark Butterfly

North America


Apodemia mormo langei


  • Habitat destruction
  • Invasion of exotic plant species
  • Tourist disturbance

From less than 200 individuals in 2008, what only remains of the Apodemia Mormo Langei or more commonly known as Lange’s Metalmark Butterfly is not more than 30 in total population (as of 2011 reports). This brightly-coloured winged insect which was named after Henry Lange of the University of California at Davis was first discovered in 1933.

The almost extinct California endemic butterfly exclusively lives in a tiny strip of riverbank in the San Francisco Bay Area. There is no other known place that serves as a habitat for this subspecies of the Mormon Metalmark from the Riodinidae family.

Land clearing has had devastating impacts on butterfly populations, resulting in limited host plants for egg laying, inadequate nectar sources, and insufficient food for larvae. And as more exotic plant species replace native plants such as buckwheat (which is an essential source of nectar and pollen), this has also made population recovery a very difficult process.

This was aggravated by the presence of tourists within and around the surrounding areas. The fragile sand dune habitat of the Lange’s Metalmark Butterfly became exposed to littering, trampling, and other forms of disturbances. Severe damage to plant life was even evident during the rescue attempt of another endangered species – ‘Humphrey the Humpback Whale’ – which was stranded for a time in the Sacramento River.