In tree holes, leaf scraping scirtid beetles increase the rate at which leaf litter is converted to fine particles, which may benefit fine particle feeding mosquitoes if these fine particles are valuable to mosquitoes. We tested whether the products of scirtid feeding are a valuable food resource for mosquito larvae [Ochlerotatus triseriatus (Say)] by introducing different amounts of scirtid feces to mosquito larvae and measuring mosquito performance. Mosquito larvae survived longer and developed to later instars in treatments with many scirtids (and, therefore, a lot of feces) compared to treatments with few or no scirtids. This result suggests that scirtid feces (and attached microorganisms) constitute a valuable food resource for O. triseriatus. Thus, other members of tree hole communities may have complex effects on the population growth of O. triseriatus.