Subject: Rainbow larva
Location: Southwest Louisiana
April 18, 2014 6:35 pm
Located these beauties munching on a small tree a few hundred yards from the coast here in southwestern Louisiana. Relatively small at less than a 1/2 inch. Not very active and pretty much play dead when disturbed. Internet search turned up nothing. Any ideas?
We were just going to write back that this is the larva of a Leaf Beetle in the family Chrysomelidae, but we decided to continue searching for its species identity. After a bit of searching, we found a matching image of a Groundselbush Beetle Larva, Trirhabda bacharidis, on BugGuide, and we are confident that it is the correct identification for your individual. According to BugGuide: “larvae and adults feed exclusively on leaves of Baccharis (Asteraceae) and it has been “Introduced into Australia and Asia to control Baccharis.” We thought this was a new species for our site, but we were wrong.