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Photo#394571
Is this Trirhabda diducta? - Trirhabda eriodictyonis - male

Is this Trirhabda diducta? - Trirhabda eriodictyonis - Male
Claremont, Los Angeles County, California, USA
April 17, 2010
This beetle was on Yerba Santa, Eriodyction trichocalyx, in Coastal Sage Scrub at the Claremont Colleges' Robert J. Bernard Biological Field Station. Photographed about 9:00 a.m. We had previously identified this beetle as Trirhabda diducta, but I've noticed that markings on the elytra are not as distinct as those shown on the T. diducta species page. I do not, however, have a sense of the normal range of color variation within the species. If someone could confirm that is T. diducta or let us know what it is if it's something else, we would very much appreciate it! We are in the process of documenting invertebrates at the Field Station (http://www.bfs.claremont.edu/biota/inverts/), and we'd like our list to be as accurate as possible.

Images of this individual: tag all
Is this Trirhabda diducta? - Trirhabda eriodictyonis - male Is this Trirhabda diducta? - Trirhabda eriodictyonis - male

This is a male
One can tell from the shape of the occipital spot (in T. eriodictyonis: hour-glass shaped for males, linear for females...according to pg. 120 of Hogue(1)).

 
Thanks!
Cool! I've edited the post to indicate that this is a male.

Moved
Moved from Beetles.

Hi Nancy,
I think this is T. eriodictyonis which has been recorded from the San Gabriels, including nearby San Dimas. T. diducta and eriodictyonis are considered sister taxa. Both spp. use Eriodictyon as food source, and their distribution overlaps in CA and UT.
A year ago I keyed out some specimens from three locations in the Transverse Ranges and arrived at eriodictyonis. I also raised some larvae, and took field photos, but then forgot about it. I noticed an interesting gender difference acc. to which your beetle is probably a male. The type is a female from Pasadena, CA; See INFO page.
P.S. I don't know how this happened, but after editing my comments this appeared twice.

Probably T. eriodictyonis
which has been recorded from the San Gabriels, including nearby San Dimas. T. diducta and eriodictyonis are considered sister taxa. Both spp. use Eriodictyon as food source, and their distribution overlaps in CA and UT.
A year ago I keyed out some specimens from three locations in the Transverse Ranges and arrived at eriodictyonis. I also raised some larvae, and took field photos, but then forgot about it. I noticed an interesting gender difference acc. to which your beetle is probably a male. The type is a female from Pasadena, CA; See INFO page.

 
Thanks for the ID!
Hi, Hartmut! I had wondered if this could be T. eriodictyonis, but the only photo I could find when I posted was the type specimen, and I personally couldn't tell much from that. Thanks for the ID and for posting your photos!