We tested the home-field advantage (HFA) hypothesis in decomposition of Pinus densiflora and Quercus acutissima leaf litter, insect frass excreted by Dendrolomus spectabilis and Lymantria dispar, and their mixtures on the soil collected underneath the two tree species. We detected a HFA in decomposition of Q. acutissima litter. We also found the evidence indicating that decomposers in each soil would have specialized to decompose the litter derived from tree species above them. In contrast, there was no HFA in decomposition of insect frass and litter-frass mixtures. Mixing with D. spectabilis frass non-additively decelerated, and mixing with L. dispar frass non-additively accelerated decomposition of the mixtures, independent of soil and litter types. These indicate that insect frass may disturb to shape and maintain the HFA in litter decomposition, and therefore, insect frass may influence the carbon and nutrient cycling in forest ecosystems through the indirect effect of frass-induced changes in soil-litter interactions.