Submitted to: Western North American Naturalist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/25/2010
Publication Date: 12/31/2010
Publication URL: http://hdl.handle.net/10113/47793
Citation: Zack, R.S., Strenge, D., Landolt, P.J., Looney, C. 2010. European Earwig, Forficula auricularia L. (Dermaptera: Forficulidae) at the Hanford Reach National Monument, Washington State. Western North American Naturalist. 70(4):441-445. Interpretive Summary: The European earwig has been introduced into North America and is widespread in areas of the northeast and western United States. As an invasive pest with little natural controls, the insect can be a significant crop pest and also be ecologically disruptive at high densities. Researchers at the USDA-ARS Laboratory,Wapato, Washington, in collaboration with scientists at Washington State University, Pullman, Washington, determine the presence, range, and densities of European earwigs in the Hanford Reach National Monument as a means to further assess its invasive nature and pest potential. Results showed that the earwig is generally present within the Monument, but is most prevalent in disturbed areas in association with invasive weedy plant species, and is present but infrequent in less disturbed habitats characterized as shrub-steppe habitat. This information provides a first assessment of the pest’s status in this protected habitat, the potential for movement between native lands and adjacent irrigated agriculture, and serves as a comparison to earwig population assessments in commercial agricultural.
Technical Abstract: The European earwig, Forficula auricularia L., was surveyed using pitfall traps at three sites at the Hanford Reach National Monument in south central Washington state. Pitfall traps were collected weekly from April 2002 through April 2003. The earwig was consistently taken during all months of the year at a disturbed, weedy site along the Columbia River (White Bluffs Ferry Site) but was rare or not collected in two, less disturbed shrub-steppe habitats. Highest numbers occurred during April/May when immatures accounted for the majority of the catch; immatures reached the adult stage during mid-July and the species is univoltine at the site. Possible reasons why earwigs have not colonized the Monument's shrub-steppe habitat may include its arid climate with lack of available moisture, especially for breeding purposes, and a lack of burrow sites.