PROJECT SUMMARY Aedes aegypti is the primary mosquito vector of viruses that cause Zika, chikungunya, yellow fever, and dengue, the most widespread and significant arboviral disease in the world. Female mosquitoes differ from males in morphological, physiological, and behavioral traits that facilitate reproduction and the transmission of pathogens. Thousands of putative long non-coding RNA (lncRNA) genes were recently identified in the A. aegypti genome, including a number that reside in the sex-determining M/m locus region. Few of these lncRNA genes, once considered dark matter, have been functionally validated or characterized. This study examines the hypothesis that M/m locus region lncRNA genes function in a sex-specific manner in adult females. The aims of this study include: (1) completion of an RNAi-based large-scale screen to identify lncRNAs that are required for adult female behavior or viability and (2) characterization of the function of these genes through manipulation of gene expression in adult females. Pursuit of these aims will involve the development of novel technology for sugar-baited delivery of yeast that enables manipulation of lncRNA transcript levels. This research program, the first study to functionally characterize lncRNAs in adult mosquitoes, will promote the elucidation of new gene targets for mosquito control and the development of new methods to manipulate the expression of these genes. The strategies employed in this investigation, which could be applied to the study of other lncRNAs, vector insect species, and biological processes of vector importance, will help promote a paradigm shift that may result in the functional validation of many lncRNA genes in insects of medical importance.