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Photo#381824
Beetle larva (Trirhabda?) on Coast Goldenbush (Isocoma menziesii) - Trirhabda

Beetle larva (Trirhabda?) on Coast Goldenbush (Isocoma menziesii) - Trirhabda
Carpinteria Salt Marsh, Santa Barbara County, California, USA
April 3, 2010
Size: 12mm
I came across a bunch of these larvae feeding on Coast Goldenbush (Isocoma menziesii). They were near a lot of Trirhabda flavolimbata larvae feeding on Coyote Brush (Baccharis pilularis), and to my eye the larvae feeding on the two plants were indistinguishable. (See this T. flavolimbata larva that I photographed a year ago in almost the same location, for example.)

I see from the Trirhabda page that host plant is an important factor in determining species, that Asteraceae (which includes I. menziesii) are among its hosts, and that a (now dead, sadly) link had an image of an unidentified member of Trirhabda, referring to it as common on Isocoma venetus, which I gather is either a close relative of, or a synonym for the same species as, I. menziesii.

Anyway, I'm curious if I'm correct in assuming this is a member of Trirhabda, and if I could get some help figuring out what species it is. Thanks.

Images of this individual: tag all
Beetle larva (Trirhabda?) on Coast Goldenbush (Isocoma menziesii) - Trirhabda Beetle larva (Trirhabda?) on Coast Goldenbush (Isocoma menziesii) - Trirhabda

Moved
Moved from Trirhabda.

Moved
Moved from ID Request.

genus looks good
!

Very similar
to the Trirhabda larvae currently on Enselia here in AZ. Easy to raise from the instar you show, just keep them in a container with food, they'll pupate and hatch in a couple of weeks