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Upcoming Events

Photos of insects and people from the 2022 BugGuide gathering in New Mexico, July 20-24

National Moth Week was July 23-31, 2022! See moth submissions.

Photos of insects and people from the Spring 2021 gathering in Louisiana, April 28-May 2

Photos of insects and people from the 2019 gathering in Louisiana, July 25-27

Photos of insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Previous events


Species Rhinocyllus conicus - Thistle Head Weevil

what weevil? - Rhinocyllus conicus Curculionidae, dorsal - Rhinocyllus conicus Fuzzy fat beatle? - Rhinocyllus conicus ID help please - Rhinocyllus conicus ID help please - Rhinocyllus conicus ID help please - Rhinocyllus conicus ID help please - Rhinocyllus conicus Rhinocyllus conicus ? - Rhinocyllus conicus
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
No Taxon (Series Cucujiformia)
Superfamily Curculionoidea (Snout and Bark Beetles)
Family Curculionidae (Snout and Bark Beetles)
Subfamily Lixinae
Tribe Rhinocyllini
Genus Rhinocyllus
Species conicus (Thistle Head Weevil)
Explanation of Names
Rhinocyllus conicus (Frölich 1792)
4-6.5 mm(1)
native to w. Palaearctic (Mediterranean basin to c. Europe & Turkmenistan), introduced in NA for weed control, now widespread, except se US(2)
on thistles (Carduus, Cirsium spp.)(2); released in NA to combat the noxious musk thistle (Carduus nutans)
Life Cycle
Univoltine; overwinters as adult. Female lays 100-200 eggs. Larva develops in flower heads; images of various stages
Controversial biocontrol agent used against noxious thistles in the genera Carduus, Cirsium, Onopordum, and Silybum. First introduced to the US in 1969 and now widely established, the weevil was found to be very effective in reducing the spread of invasive thistles, but also prone to attack native Cirsium spp. No longer recommended; releases prohibited in many areas.(3)
Print References
Louda S.M., Kendall D., Connor J., Simberloff D. (1997) Ecological effects of an insect introduced for the biological control of weeds. Science 277: 1088-1090.
Rose K.E., Louda S.M., Rees M. (2005) Demographic and evolutionary impacts of native and invasive insect herbivores: a case study with Platte thistle, Cirsium canescens. Ecology 86: 453-465.
Internet References
Fact sheet (Kok YYYY)(3) [use with caution]