Onychobaris langei

Lange's El Segundo Dune Weevil

Family: Curculionidae · Class: Insecta · Order: Coleoptera

Conservation status: G1 S1

Lange's El Segundo dune weevil (Onychobaris langei) is a small, endemic beetle species restricted to coastal dune habitats in southern California. This weevil measures approximately 3-4 millimeters in length and displays the characteristic curved snout typical of weevils. The body is dark brown to black with a robust, oval shape adapted for life in sandy environments. The species has an extremely limited range, historically occurring only in the El Segundo dunes system of Los Angeles County. Current populations are restricted to remnant dune habitat at Los Angeles International Airport (LAX) and adjacent areas. The original El Segundo dunes once extended across approximately 3,200 acres but have been reduced to less than 200 acres due to urban development and airport expansion. Lange's El Segundo dune weevil inhabits active and semi-stabilized coastal sand dunes dominated by native vegetation. The species is closely associated with specific host plants in the sunflower family, particularly telegraph weed (Heterotheca grandiflora) and beach bur (Ambrosia chamissonis). These dune systems are characterized by loose, fine-grained sand with sparse vegetation cover and are subject to natural wind disturbance that maintains the dynamic dune structure essential for the weevil's survival. Adult weevils are most active during spring and early summer months. Females deposit eggs on or near host plants, where larvae develop by feeding on plant tissues. The species likely completes one generation per year, with adults overwintering in the sandy substrate. Like other weevils, both larvae and adults feed on their host plants, with larvae typically consuming roots or stems while adults feed on leaves and flowers. The species' ecology remains closely tied to the natural disturbance cycles that maintain open dune habitat. Lange's El Segundo dune weevil has a Global Rank of G1 and State Rank of S1, indicating it is critically imperiled. The species faces severe threats from habitat loss and fragmentation due to urban development, airport operations, and recreational activities. The remaining habitat is highly vulnerable to invasive plant species that alter dune structure and native plant communities. Air pollution, human trampling, and altered hydrology from surrounding development further degrade habitat quality. Climate change poses additional threats through sea level rise and changing precipitation patterns that could affect dune dynamics. Conservation efforts focus on habitat restoration and protection of remaining dune areas, including invasive species control and establishment of protective barriers. The species' extremely small population size and limited range make it vulnerable to extinction from catastrophic events or continued habitat degradation. Ongoing monitoring and adaptive management are essential for the species' long-term survival.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.