Metallic rainbow beetle larvae in GA, USA wetland.
Location: Augusta, GA, USA
February 17, 2012 7:04 pm
Hi, I found these larvae in large nests (clumps of dried leaves held together with webs) in a common shrub in an Augusta, GA wetland on February 11, 2012. I don’t know the name of the shrub, but I know it’s very widespread in wetlands in the southeastern USA. At any rate, these nests were very common throughout the shrubs, with several nests per shrub, and each nest seems to contain several larvae in various instars. The largest larvae I saw were ~1 cm long.
WE are posting your photos as unidentified because we haven’t the time to research this at the moment. Perhaps one of our readers will supply an answer in our absence. The nest is quite a curiosity. We wish you could supply the name of the plant.
That is the larva of Trirhabda bacharidis (Weber), a leaf beetle which is host specific to salt bush, Baccharis halimifolia. Don’t think it has anything to do with the “nests.”
It is interesting that the species name of the Leaf Beetle is derived from the generic name for the host plant. We located this Coleopterists Bulletin article entitled “The Host Specificity and Biology of Trirhabda bacharidis“. BugGuide calls it the Groundselbush Beetle.
Update from Sarah
March 31, 2011
I apologize for my tardy reply, but I believe the mystery is mostly solved. I took the plant to a botanist and the bug to an entomologist at Georgia Southern University. The botanist said the plant is Baccharis halimifolia, eastern baccharis. The entomologist said he thinks the larvaea are Chrysomelid beetles, but he can’t identify them to species unless they’re grown out to adults.