Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Trirhabda - Trirhabda flavolimbata

Trirhabda - Trirhabda flavolimbata
Burton Mesa Management Area, near Vandenberg Village, Santa Barbara County, California, USA
April 28, 2003
Landed on my clothing, near a vernal pool.
This looks similar to the image of Galerucella nymphae by Terry Thormin, , save for the color of the elytra.
G. calmariensis and G. pusilla (also not green as far as I've seen), native to Europe and Asia, have been used to control Purple Loosestrife (Lythrum salicaria).
P.S. I should have moved this to the genus page some time ago. Candidates for species are luteocincta, labrata, and possibly flavolimbata. Their colors may vary from green to metallic blue, and may differ only in male genitalia. According to Michael Catarino (Santa Barbara Museum of Natural History, & California Beetle Project), both T. labrata and luteocincta have been collected in coastal Santa Barbara county.

Happy New Year, Hartmut :-)
I've been thinking about your post here for a good while. And I've come to believe it's likely you were on the right track with your earlier remark that T. labrata is a good candidate.

The large pronotal spots, sparse elytral pubescence, and highly "polished"-looking pronotum point in that direction. It actually goes to T. labrata in Blake's key via couplet's: 1, 12, 15, 16, 21. (And also in the virtually equivalent key of Wilcox(1).)

Also Blake mentions "Guadalupe" as a location, which is just north of Burton concert with M. Caterino's record(s?) of T. labrata in that area. And while the host of T. flavolimbata is presently considered to be Baccharis pilularis only...the hosts of T. labrata are recorded to be both B. pilularis *and* Ericameria ericoides, the latter also being present at Burton Mesa. So it could have flown onto you from either plant :-)

I can see why Boris voted for T. flavolimbata based on the type image from the MCZ. I concurred for a long time...but note the comment at the end of the 3rd paragraph here.

I've been working on Trirhabda lately...thus all the thoughts above. I'd love to hear what you think, after you get a chance to go through the above and digest it a bit.

Happy New Year to you, Aaron !
Looks like you've done a great job researching this!
I've only had time for a cursory glance, but will l look more carefully when I have more time.

Moved from Trirhabda.

I vote for flavolimbata
. . . after I have seen a type specimen of it.
T.luteocincta image also available there, looks pretty different.


also looks like
Trirhabda geminata here but unfortunately we're not the Chrysomelid expert you were looking for! :)
Galerucella are 4-6mm, while Trirhabda are 7-10mm

may be a push in the right direction. Though both genera (Galerucella, Trirhabda) are closely related and in the Galerucinae tribe of the
Chrysomelidae, size does make a difference ('My' beetle is 9-10mm).

I don't think it is T. geminata; wrong color, distribution, and host plant doesn't occur this close to the coast. T. luteocincta and T. flavolimbata occur in CA. Both may be green or metallic blue. T. luteocincta feeds on Artemisia -here mostly A. californica/California Sagebrush- (Asteraceae,Anthemidae), and T. flavolimbata feeds on Baccharis pilularis. Both plants are present in Burton Mesa Chaparral, where I found the beetle.

Note: Species and hostplant information from an article in CHRYSOMELA #40/41, April 2001 [Will Molecular Phylogenetics Elucidate Hostplant Shifts in Trirhabda LeConte (Chrysomelidae, Galerucinae)?, by Z. Swigonova and K.M. Kjer]

Finally, thanks for your suggestion!

Trirhabda species
Note that the third antennal segment is shorter than the fourth (a distinguishing characteristic of Trirhabda, according to the key to Galerucinae at Auburn University). In species of Galerucella, Ophraella, and Pyrrhalta, the third antennal segment is longer than the fourth.

Thanks for this, Robin,
I just looked at the key, and think that Trirhabda is correct.

I think that it is safe to assume that it belongs in the Galerucinae subfamily.

You bet it is, and thank you for moving it.