In Drosophila melanogaster, seminal peptides secreted by the male accessory glands can control post-mating behaviour in females, such as inhibiting remating. As exosomes (a type of secretory vesicle) are known to mediate intercellular signalling in various species, Corrigan et al. used a fluorescent exosomal marker to track whether exosomes had a role in this male-to-female communication. Exosomes were observed to be secreted into the accessory gland lumens and were released during mating, when they fused with sperm cells and interacted with the female epithelium. Blocking exosome production reduced the ability of males to modulate female behaviour, thus confirming their functional importance.