Supplementary Material for Palmateer et al., 2026

Article SummaryWe examined how genes and circuits shape courtship behaviors in Drosophila melanogaster and Drosophila simulans. We focused on the fruitless gene, which is expressed in the nervous system and controls male courtship by encoding male-specific transcription factors (FruM). fru-expressing neurons in hybrids closely resembled those in Drosophila melanogaster indicating largely shared neuronal architecture. We identified both shared and species-specific FruM target genes, including odorant receptor genes bound by FruM in a species-specific manner. A genetic screen in Drosophila melanogaster, where we silenced odorant receptor neurons that co-express fruitless, revealed sensory neuron populations that direct quantitative differences in courtship towards Drosophila simulans. Neuroanatomical mapping shows that odor information is relayed to different higher order brain regions. The results uncover molecular and neural circuit mechanisms underlying species differences in behaviors.