Fruit fly larvae can taste ribonucleosides, the building blocks of gene transcripts, according to a new study publishing on August 7 in the open-access journal PLOS Biology by Hubert Amrein and Dushyant Mishra of Texas A&M Health Science Center and their colleagues. Moreover, the ability to detect ribonucleosides in the environment helps promote the rapid growth needed by developing larvae and dramatically increases their survival.