Thistle Head Weevil
( Rhinocyllus conicus )


2009-0516-49064901-COL00366-Rhinocyllus_conicus[1303h51s,F,A,plant-thistle]{EXD}-G.jpg

PHOTO COMMENT

IDENTIFICATION
Identification:Rhinocyllus conicus
(Frölich, 1792)
Common Name:Thistle Head Weevil
Life Stage:(A) adult

PHYLOGENY

Phylum:Arthropoda
Class:Insecta
Superorder:Holometabola
Order:Coleoptera
Suborder:Polyphaga
Family:Curculionidae
Subfamily:Lixinae
Tribe:Rhinocyllini
Genus:Rhinocyllus
Taxon Code:COL00366
ITIS/TSN:618891

LOCATION DETAILS
Location Name
BSA Camp Royaneh, BSA Camp Royaneh, 4600 Scanlon Rd., Cazadero
County:Sonoma County
ECI Site#:CA49064901

RECOGNITION
Description
Adult: Beetles have a rostrum (snout) that is shorter and more stout than the rostrums of many of our native weevils. Bodies are dark brown with small tufts of yellow setae (hairs) and patches of lighter mottling. The adult beetles can be seen very plainly on the plant.
Body Length
Adult: 5-8 mm.
Similar Taxa
Similar to Larinus planus, but distinguished by the very short rostrum. Freshly emerged specimens covered with yellow, dusty secretion.

BIOLOGY
Larvae develop in flower heads of its host plant.
Habitat
Common on thistle in the spring.
Range
European by origin, purposely introduced for control of musk thistle (Carduus nutans). However, it has been discovered to also attack native Cirsium spp. and is no longer recommended for distribution.
Active Period
Around the flowering season of its host plants.
Development
Female adults lay around 100 eggs on or near the heads of thistle flowers. Emerging larvae burrow into the flower, feeding on tissues and the developing seeds.

CREDITS
Photographer
Eddie Dunbar
Insect Sciences Museum of California

References
Species Rhinocyllus conicus - Thistle Head Weevil. (http://bugguide.net/node/view/92634). Accessed September 24, 2016. .
ITIS.


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