Researchers from the Federal University of São Carlos (UFSCar) and São Paulo State University (UNESP) have isolated four fungi from the gut of the cotton bollworm caterpillar (Helicoverpa armigera) and shown, using scanning electron microscopy, that each one can alter the surface of polystyrene film. When fed expanded polystyrene, the caterpillar's gut microbiome shifted, with the yeast genus Diutina declining and potentially plastic-degrading genera including Aspergillus, Ta