Early work by Spanish researchers has identified that the larvae of the greater wax moth, a well-known pest in bee hives, was able to digest polyethylene plastic bags. Methylene bridges are found in both beeswax and many plastics including polyethylene. These bridges are impossible for most organisms to break down, however it is suspected that the greater wax moth has made it possible.
For more information please read the full article: Plastic-eating caterpillars could save the planet