Calibrating the data logger…
Herbivorous insects are among the most successful–and destructive–organisms on Earth. One third of all animal species are herbivorous insects, and they collectively remove over 20% of plant biomass in both natural and agricultural systems. Yet we know surprisingly little about how herbivory originates: how insects transition from ancestral diets like detritus, microbes, or other insects to feeding on living plants. To illuminate this process, we are comparing the genomes and traits of herbivorous insect species with closely-related non-herbivorous relatives, in order to infer the changes that occur when insects evolve to be herbivorous. In particular, we are focusing on fly species closely related to Drosophila melanogaster, a microbe-feeding fly that is the leading model organism for genetics studies. One of these focal herbivorous species, Scaptomyza nigrita, has been studied for decades at RMBL where it feeds exclusively on wild mustard plants along alpine streams and seeps. I plan to collect S. nigrita flies at RMBL, sequence their genome, and use this genome in a broader analysis with other herbivorous and non-herbivorous fly genomes to help illuminate the genetic changes that allow insects to feed on living plants. While our primary goal is to understand how herbivory evolves, this work also has practical implications. By identifying genes and traits essential for herbivory, we aim to uncover new targets for protecting crops from insect pests. More broadly, by studying how organisms adapt to novel diets, we also hope to shed light on genes that mediate the link between diet and health–which may inform our understanding of the relationship between diet and disease in humans.