Role of the intestinal microbiome in polyethylene degradation by caterpillar larva of the greater wax moth (Galleria mellonella)

Recently, a few insects, including the caterpillar larva of the greater wax moth Galleria mellonella, have been identified as avid \"plastivores\". Interestingly, these caterpillars are able to ingest and metabolize polyethylene at unprecedented rates. While it appears that G. mellonella plays an important role in the biodegradation process, the contribution of its intestinal microbiome remains poorly understood and contested. In a series of experiments, we present strong evidence of an intricate relationship between an intact microbiome, low density polyethylene (LDPE) biodegradation, and the production of glycol as a metabolic by-product. First, we biochemically confirmed that G. mellonella larvae consume and metabolize LDPE, as individual caterpillars fed on polyethylene excreted glycol, but those excretions are reduced by antibiotic treatment. Further, while the gut bacterial communities remain relatively stable regardless of diet, we show that during the early phases of feeding on LD...