Sexual traits convey information about individual quality to potential mates. Environmental and genetic factors affect sexual trait expression and perception via effects on animal condition and health. High fat diet (HFD) is one environmental factor that adversely affects Drosophila melanogaster health, and its effects on animal health are mediated through conserved metabolic signaling pathways. HFD decreases female attractiveness, resulting in reduced male mating behaviors toward HFD females. HFD also affects the ability of males to judge mate attractiveness and likely alters fly condition and sexual traits to impact mating behavior. Here we show that HFD affects both visual (body size) and non-visual (pheromone profiles) sexual traits, which likely contribute to decreased fly attractiveness. We also demonstrate that adult-specific HFD effects on male mate preference can be rescued by changing metabolic signaling. These results demonstrate that HFD alters Drosophila sexual cues to reflect concurrent effects on condition and that less severe behavioral defects can be reversed by genetic manipulations that rescue fly health. This work expands on current knowledge of the role that metabolic signaling pathways play in linking animal health, sexual traits, and mating behavior, and provides a robust assay in a genetically tractable system to continue examining these processes.

Since the initial reports that a group of small RNAs, now known as microRNAs (miRNAs), regulates gene expression without being translated into proteins, there has been an explosion of studies on these important expression modulators. Drosophila melanogaster has proven to be one of the most amenable animal models for investigations of miRNA biogenesis and gene regulatory activities. Here, we highlight the publicly available genetic tools and strategies for in vivo functional studies of miRNA activity in D. melanogaster. By coupling genetic approaches using available strain libraries with technologies for miRNA expression analysis and target and pathway prediction, researchers' ability to test functional activities of miRNAs in vivo is now greatly enhanced. We also comment on the tools that need to be developed to aid in comprehensive evaluation of Drosophila miRNA activities that impact traits of interest.