Sweeney Ridge, Golden Gate National Recreation Area, San Bruno, San Mateo County, California, USA
May 29, 2009
A little under 2 years ago I became fascinated with this species, which inspired me to make my first BugGuide post
Recently, I noticed their larvae on many Coyote Brush plants all along a hike of a few miles. So I thought I'd get some photos to complement the earlier adult Trirhabda
images of many BugGuide contributors.
Checking out the guide page today, I found there have been recent contributions of larval images from Santa Barbara, CA on 3/29/09
and Santa Clara, CA on 4/25/09
. Here are two more from San Bruno, CA on 5/29/09. As would be expected, the phenology is moving northward as the season progresses. Another two images of a paler larva from the same locale on 6/4/09 appear here
species are known to be restricted in their host plants, with the larva of different species typically associated with one (or a few) host(s) in a given genus. The host plant of Trirhabda flavolimbata
is Coyote Brush (Baccharis pilularus
) in the composite family (Asteraceae). Coyote Brush is a dominant shrub in coastal scrub communities along much of the length of California.
Since first getting to know Trirhabda flavolimbata
, I've almost always seen it on Coyote Brush...with the exception of one time late in the season (Septermber) when 10+ adults were cavorting on branches of Aster chilensis
, another composite. (I don't know what they were doing there, the leaves seemed uneaten on the plant.)