Figure 2. Smell of yeast affects female sexual receptivity via the ionotropic odourant receptor family.

(a) Mean number of copulations of one female and one male Canton-S exposed to yeast vapour and/or nutritional yeast over 24 hr. Air was bubbled either through sterile yeast medium “Medium air” or through a yeast culture “Yeast air”. Yeast was subtracted from, “Food − yeast” (White dots), or added, “Food + yeast” (Black dots), to the fly food recipe. Number of pairs tested ranged from 12–24. (b) Mean number of copulations of one Orco⁻ or one Orco⁻ with a genomic rescue construct (Orco⁻, p{Orco⁺}) female housed with one wild-type Canton-S male. Yeast was included in the food. Yeast and medium air conditions were tested as in (a). The number of pairs tested ranged from 27–29. (c) Mean number of copulations of one Ir8a⁻ or one Ir8a⁻ with a genomic rescue construct (Ir8a⁻, p{Ir8a⁺}) female housed with one wild-type male tested as in (b). Number of pairs tested ranged from 25–27. Error bars indicate S.E.M. The post-hoc effect of air within one food condition or genotype was tested using mixed effect models, p values are reported above the graphs. See Table S1 for full statistics of main effects and post-hoc models.