The Tibetan Plateau is one of the areas in the world most sensitive to global warming. Dung beetles are the most abundant decomposer species group responsible for cattle dung removal in the Tibetan alpine meadow, and are critical to nutrient cycling and primary production of the grazing system. This study evaluates the possible effects of global warming on early life-history traits of dung beetles. We established three warmed open-top chambers (OTCs, about 2.3 °C higher than the control) and three ambient OTCs, each containing nine fresh dung pats that were bagged with a nylon screen (0.2 mm in mesh size). Twenty adults of a dominant coprophagous beetle species, Aphodius erraticus (Coleoptera: Scarabaeidae) had been put into each dung bag at the beginning of the experiment and the timings of egg-laying and hatching, and egg and larval size were followed for 80 days. Artificial warming advanced egg-laying and hatching by 4.1 and 7.2 days, respectively; warming decreased egg and larval size by 22.1% and 33.4%, respectively. This short-term study demonstrates that early lifehistory traits of A. erraticus are sensitive to artificial warming, which suggests that global warming may also change life history traits of other organisms in detritus-based systems.