Drosophila (Drosophila) nigrosparsa is a habitat specialist restricted to the European montane/alpine zone (Bächli 2008). Mountain biodiversity is considered highly vulnerable to ongoing climate warming (IPCC 2013), and organisms at high altitudes have only limited possibility to shift to cooler habitats at elevations above (Pertoldi & Bach 2007). For such species, rapid evolution may offer a solution for long-term survival. We are establishing D. nigrosparsa as a model system to test the extent and tempo of adaptive evolution under thermal stress in the laboratory. In this study, we used Illumina high-throughput sequencing to assemble the species’ transcriptome using the pooled mRNA from 22 developmental and physiological stages.