Vol. 1 10, No. 2, March & April, 1999 103 DISTRIBUTION AND CLASSIFICATION OF AQUATIC WEEVILS (COLEOPTERA: CURCULIONIDAE) IN THE GENUS EUHRYCHIOPSIS IN WASHINGTON STATE 1 Mariana Tamayo 2 , Charles \V. O'Brien 3 , Robert P. Creed Jr. 4 , Christian E. Grue 2 , Kathy Hamel 5 ABSTRACT: During the summers of 1993, 1996 and 1997, we surveyed a total of 66 sites in Washington State to determine the presence and distribution of the aquatic weevil Euhrychiopsis lecontei. E. lecontei was found in 8 sites in 1993, all in eastern Washington. In 1996 the weevil was found in 9 lakes, 2 of which where located in western Washington. During 1997, we found weevils in 14 sites, all except one were located east of the Cascade Mountains. Previously, the genus Euhrychiopsis was considered to have 2 species, lecontei and albertanus. However, examination of the male genitalia from specimens of both species in this genus from 20 populations across North America showed no differences within or between populations. Therefore, there is only one valid species in the genus Euhrychiopsis, namely lecontei. E. albertanus is a junior synonym [NEW SYNONYMY]. In recent years, the aquatic weevil Euhrychiopsis lecontei (Dietz) has been receiving a great deal of attention from both researchers and resource managers as a potential biological control agent of Eurasian watermilfoil (Myriophyllum spicatum L.), an aquatic macrophyte native to Europe, Asia and northern Africa (Couch and Nelson 1986). This weevil is native to North America and has been associated with declines of M. spicatum in the continent (Creed and Sheldon 1 995, Lillie 1 996, Jester et al. 1 997, Creed 1 998). In addition, most of the unex-plained declines of M. spicatum in North America have occurred within E. lecontei's original range (Creed 1998). Laboratory and field studies conducted in Vermont and Minnesota have concluded that this weevil is a watermilfoil specialist and that it can have a negative impact on Eurasian watermilfoil (e.g. Creed and Sheldon 1995, Sheldon and Creed 1995, Newman et al. 1996, Solarz and Newman 1996). Given the promising results seen in Vermont and Minnesota and that Eur-asian watermilfoil is currently found in 86 lakes and rivers throughout Wash-ington State (Parsons 1997), E. lecontei may be an alternative for controlling 1 Received April 30, 1998. Accepted July 4, 1998. 2 Washington Cooperative Fish and Wildlife Research Unit, School of Fisheries, University of Washington, Box 357980, Seattle, WA 98 195-7980 USA. Correspondence to M. Tamayo. -Entomology-Biological Control, Division of Agricultural Sciences, College of Engineering Sci-ences, Technology and Agriculture, Florida A&M University, Tallahassee, FL 32307-4 100 USA. 4 Department of Biology, Appalachian State University, Boone, NC 28608 USA. ^ Water Quality Assistance Program, Washington Department of Ecology, P.O. Box 47600, Olym-pia, WA 98504 USA. ENT. NEWS 1 10(2) 103-1 12, March & April, 1999
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