Aquatic biologists frequently assess macroinvertebrate diets to inform energetics, secondary production, and trophic ecology studies. Dietary information is typically obtained via stable-isotope analysis or by identifying gut-contents under a microscope. However, neither technique provides high-resolution data. The diets of shredding insects can rarely be resolved beyond vascular plant tissue, while the nutritionally important fungal component is often under-sampled or ignored. Using shotgun metagenomics to understand detritivore trophic ecology could provide a faster and more taxonomically robust way to evaluate detritus-based food webs. Shotgun sequencing allows researchers to sample the environment without prior knowledge about what is there, while detecting rare diet components. Pycnopsyche, a common genus of shredding caddisfly found in forest streams in the eastern U.S.A., relies on litter and associated fungi for its energetic requirements. We are collecting Pycnopsyche larvae from a developing cohort (second- to fifth-instar) in a single headwater stream at the Coweeta Hydrologic Laboratory, North Carolina, U.S.A. DNA from the caddisfly guts and stream leaf litter is being extracted and sent for whole-genome shotgun sequencing. We will compile chloroplast genomes from our litter species, along with fungal mitochondrial genomes from GenBank and fungal nuclear genomes from the JGI MycoCosm repository. Developing a database for our genomes and mapping our shotgun reads will identify the litter and fungi species—or at least genera—found in caddisfly guts and their relative abundance compared to samples taken from the surrounding environment. Our study tests the potential of shotgun metagenomics to inform stream trophic dynamics with far higher resolution than that possible using traditional techniques.