Although polystyrene (PS) is considered a non-biodegradable material, recent work has shown the degradation capacity of this material by microorganisms, especially those that are part of the natural microbiota of the digestive tract of some invertebrates. The present work sought to evaluate the growth of the larva of the mealworm (Tenebrio molitor) and its bacteria, using PS as the sole source of carbon. In this way it was possible to demonstrate the consumption of PS plates by the larva, found in holes and tunnels in the material, however, nutritionally it is not enough for the larva to gain biomass, notably reducing its size and time survival. Similarly, bacteria isolated from the digestive tract of T. molitor presented the ability to generate biofilms o n PS s heets, g enerating c hanges ( cracks, holes, etc.) in them, which were observed under scanning electron microscopy (SEM), indicating the possible use of this material as a carbon source for its growth.