Insect taste organs display incredible morphological and functional diversity between species, as well as having variable sex-specific functions within species. In light of these differences, we have been addressing open questions about the evolution of gene expression in taste tissues. Our focus has been on closely-related species where insights into the early stages of sensory diversification can still be detected. We have generated transcriptomes for four sensory tissues (proboscis + maxillary palp, forelegs, ovipositor, and larval head) for males and females of six ecologically diverse Drosophila species. Species comparisons revealed pervasive gene expression changes associated with both morphological and chemosensory functions. In proboscis for instance, ~ 27% of 1:1 orthologs have changed in expression at least once over the past 15 million years. When examining expression breadth according to gene ages, we found that young genes and highly duplicated gene families were disproportionately tissue specific, suggesting a role in taste organ specialization. Given the roles that these organs play in sex-specific behavior, we examined the patterns of sex-biased gene expression. Patterns of sex-biased expression vary remarkably among taste tissues and do not reflect the phylogenetic relationship of the species. To relate these tissue-level expression changes to evolutionary modifications at the level of cell populations, we are generating cross-species single cell atlases. Analyses of these data are revealing species-specific elevated gene expression associated to the expansion of single neuron populations as well as surprising cell-specificity of sex-biased genes. Together, our work demonstrates the power of combining cross-species bulk RNA-sequencing with matched single cell RNA transcriptome data for understanding the origins of chemosensory diversification.