The Drosophila melanogaster female pheromone mediates aggregation of males and females at oviposition sites

Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster is attracted to fermenting fruit for feeding and egg-laying. Long-range attraction of flies of both sexes to food patches is greatly enhanced by the species-specific, volatile female pheromone (Z)-4-undecenal (Z4-11Al). Twin olfactory receptors, two isoforms of DmelOR69a, with dual specificity for food odorants and pheromone, are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication. Intriguingly, we ourselves readily perceive Z4-11Al, which is released at subnanogram amounts per hour. Since only females produce this scent, we reliably distinguish the scent of male and female flies.

A screening of all human ORs shows that the most highly expressed human olfactory receptor hOR10A6 is tuned to Z4-11Al. Females of an ancestral African D. melanogaster fly strain release a blend of Z4-11Al and Z4-9Al that produces a different aroma, which is how we distinguish these fly strains by nose. During matings, males become "painted" with Z4-11Al, which is how we can reliably distinguish the scent of unmated and freshly mated males. These findings have generated perspectives of how to further investigate the chemical ecology of the Drosophila melanogaster female pheromone, that continues to deliver surprises. These will be shared at the meeting.