Common NameKnotweed WeevilSeasonalityMuseum specimens were all captured in April-June, in Alberta, and are post-emergence adults.IdentificationLeConte (1876) diagnosed this relatively small species as one in which the underlying cuticle is black and covered by a thin coat of grey pubescence - Stickland Museum specimens appear to have a much more reddish-brown coat on dorsal surfaces, but this is simply because their emergence coat has not rubbed off yet (Essig, 1958). This species is distinguished by its thick rostrum, which is as long as its prothorax, and bears coarse punctures (laterally), and a prominent fovea (shallow central pit) and shallow transverse depression on its front. Antennae are situated very close to the tip of the rostrum. The overall body shape is relatively ovate (in dorsal view). The prothorax has fairly round sides, is wider than it is long, and has broad indentations in its posterior edge (for accepting leading edges of elytra). These indentations meet along the midline of the prothorax to form a very broad triangle at the medial angle. The legs of this species have femora that are moderately slender and uniform in thickness. The elytra are significantly wider than the prothorax, with moderately deep depressions where they meet the prothorax, and rounded posterior tips. Punctures in the cuticle are minute on the prothorax, with sparse, coarser punctures interspersed. The elytra have much coarser punctures in a widely spaced distribution, but arranged in longitudinal bands (striae).
Scientific NameLixus parcusCommon Name
Knotweed Weevil
Habitat
Mesic (moist) habitats among herbs and shrubs (Anderson, 1987).
Seasonality
Museum specimens were all captured in April-June, in Alberta, and are post-emergence adults.
Identification
LeConte (1876) diagnosed this relatively small species as one in which the underlying cuticle is black and covered by a thin coat of grey pubescence - Stickland Museum specimens appear to have a much more…
LeConte (1876) diagnosed this relatively small species as one in which the underlying cuticle is black and covered by a thin coat of grey pubescence - Stickland Museum specimens appear to have a much more reddish-brown coat on dorsal surfaces, but this is simply because their emergence coat has not rubbed off yet (Essig, 1958). This species is distinguished by its thick rostrum, which is as long as its prothorax, and bears coarse punctures (laterally), and a prominent fovea (shallow central pit) and shallow transverse depression on its front. Antennae are situated very close to the tip of the rostrum. The overall body shape is relatively ovate (in dorsal view). The prothorax has fairly round sides, is wider than it is long, and has broad indentations in its posterior edge (for accepting leading edges of elytra). These indentations meet along the midline of the prothorax to form a very broad triangle at the medial angle. The legs of this species have femora that are moderately slender and uniform in thickness. The elytra are significantly wider than the prothorax, with moderately deep depressions where they meet the prothorax, and rounded posterior tips. Punctures in the cuticle are minute on the prothorax, with sparse, coarser punctures interspersed. The elytra have much coarser punctures in a widely spaced distribution, but arranged in longitudinal bands (striae).
Life History
Females oviposit individual eggs into notches that they create in stems (Milne and Milne, 1980). Larvae burrow into stems, forming gall-like galleries where they then pupate (Blatchley and Leng, 1916). The adults…
Females oviposit individual eggs into notches that they create in stems (Milne and Milne, 1980). Larvae burrow into stems, forming gall-like galleries where they then pupate (Blatchley and Leng, 1916). The adults emerge to feed on the soft tissues of various plants; often different plants from those used by larvae (Anderson, 1987). Essig (1958) stated that there appears to be only one generation per year, and found that this species pupates late within the summer, with adult abundances in the western US occurring within the fall.
Conservation
Not of concern.
Diet Info
No plant associations were noted in the University of Alberta collections, but Essig (1958) stated that this species is associated with knotweed. He found that this species created oblong galls about 1 cm in length,…
No plant associations were noted in the University of Alberta collections, but Essig (1958) stated that this species is associated with knotweed. He found that this species created oblong galls about 1 cm in length, near the basal branches of this plant, often with multiple galls on a single plant. Riley (as cited by Webster, 1892) has also found that this species forms galls on Amelanchier (Saskatoon-berry bushes).
Range
McNamara (2006) listed Canadian occurrences in Alberta and Ontario. O'Brien and Wibmer (1982) provided American occurrences in IL, IN, CA, OK, TX, IA, KS, MT, NE, and SD.
Notes
The type specimen described by LeConte (1876) was significantly smaller than many of those in the Strickland Museum collections, measuring only 5.5 mm in length. This may have minor affects on the relative proportions…
The type specimen described by LeConte (1876) was significantly smaller than many of those in the Strickland Museum collections, measuring only 5.5 mm in length. This may have minor affects on the relative proportions of the body parts, as well as the prominence of punctures and depressions, when compared to his description and material.
O'Brien and Wibmer (1982) stated that Lixus pygmaeus LeConte 1876 is a junior subjective synonym of this species, but it was seldom used, so is of little concern.
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Citation
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Page Citation for Lixus parcus
Page Citation
"Species Details - Lixus parcus, University of Alberta E.H. Strickland Entomological Museum." University of Alberta Museums Search Site, https://search.museums.ualberta.ca/g/2-5974. Accessed 13 May. 2025.
References
AuthorO’Brien, C. W. and G. J. Wibmer
TitleAnnotated checklist of the weevils (Curculionidae sensu lato) of North America, Central America, and the West Indies (Coleoptera, Curculionoidea).
Publication Date1982
Series TitleMemoirs of the American Entomological Institute
Volume34
Pages382 pp.
AuthorMcNamara, J.
TitleFamily Curculionidae (snout beetles). Web-based checklist of Canadian beetle species produced by the Canadian National Collection of insects, arachnids, and nematodes.
Publication Date2006
AuthorWebster, F.M.
TitleFood plants of the Lixi.
Publication Date1892
Series TitleProceedings of the Entomological Society of Washington
Volume2
Pages339-341
AuthorEssig, E. O.
TitleInsects and mites of Western North America.
Publication Date1958
Pages1050 pp.
AuthorMilne L. and M. Milne
TitleNational Audubon Society field guide to insects and spiders (North America).
Publication Date1980
Pages989 pp
AuthorBlatchley, W. S. and C. W. Leng.
TitleRhynchophora or weevils of North Eastern America.
Publication Date1916
Pages682 pp.
AuthorAnderson, R. S.
TitleSystematics, phylogeny and biogeography of New World weevils traditionally of the tribe Cleonini (Coleoptera: Curculionidae: Cleoninae).
Publication Date1987
Pages740 pp.
AuthorLeConte, J. L.
TitleTribe IV: Cleonini.
Publication Date1876
Series TitleProceedings of the American Philosophical Society
Volume15
Pages144-160
AuthorLeConte, J. L.
TitleTribe XVIII: Ceutorhynchini.
Publication Date1876
Series TitleProceedings of the American Philosophical Society
Volume15
Pages267-284
Specimen Information
There are 4 specimens of this Species.
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4 results plotted on map in 1 marker. Note: Only records with latitude and longitude coordinates are plotted on map.