Role of host plant and oral bacteria in the gypsy moth’s interaction with hybrid poplar

We investigated two components of how bacteria may mediate interactions of gypsy moth larvae with their host plants. First, we identified several endophytic bacteria in the foliage of hybrid poplars, an important tree for biofuel production and multiple ecological services. In laboratory bioassays, one species, an Actinomycete, exerted negative effects on larvae. Second, we evaluated whether bacteria present in gypsy moth saliva could mediate inducible defensive responses of poplar to gypsy moth feeding. We identified a community of bacteria in the oral cavities of wild and lab-reared larvae, and observed induced defensive reactions to artificially administered oral secretions. However, secretions from antibiotic-fed larvae elicited similar reactions. We are currently investigating potential roles of endophytic bacteria in the inducible responses of poplar against folivorous insects.