I am working with undergraduates to do metagenomic analysis of microbes associated with cockroaches and also to examine the cockroach immune system in response to infection.
I am working on microorgansms associate with bark beetles. A recent paper on Dendroctonus ponderosae described the bacterial community associated with this insect using metagenomic analysis, and may answer the first part of your question:
Adams et al., 2013. Mountain Pine Beetles Colonizing Historical and Naïve Host trees Are Associated with a Bacterial Community Highly Enriched in Genes Contributing to Terpene Metabolism. Appl. Environ. Microbiol. June 2013 vol. 79 no. 11 3468-3475