Résumé
Although attractive scents play a crucial role in reproduction in insect‐pollinated plants, the degree of variation of this signal within and among populations remains understudied. Depending on the specifics of the reproductive system of the plant under scrutiny, it is possible to formulate predictions regarding this variation. In plants with separate sexes (dioecious species) and with highly specific pollination, one would predict (i) males to emit more scent than females, owing to sexual selection, (ii) scent bouquets to have a strictly similar composition between sexes, to guarantee efficient pollen transfer and (iii) variation of scent bouquet among populations that should mirror neutral genetic divergence. These hypotheses were tested in the European fan palm, Chamaerops humilis , by collecting scent in eight populations from three regions, Spain, Sardinia and Sicily, quantifying densities of pollinators— Derelomus sp. and Meligethinus pallidulus —and genotyping the plants on a set of neutral markers. Males emitted more scent than females. We detected some differences in bouquet composition between sexes, showing an imperfect inter‐sex mimicry in some populations. We also found a strong geographical effect, with individuals sampled in Sicily emitting a strikingly different scent bouquet, which contained high proportions of a volatile compound that was never detected in the other two regions. Geographical variation of scent composition did not mirror neutral genetic structure: Sardinian and Spanish populations emitted similar scent bouquets but displayed very high levels of genetic differentiation. On the reverse, Sicilian populations showed both strong scent differences and appeared clearly genetically differentiated from populations found elsewhere, without any depletion in neutral genetic diversity. Synthesis : Our study confirmed higher scent emission rates in males compared to females, consistent with expectations of sexual selection. However, we also discovered significant variation in the composition of the floral bouquet, which was unexpected given the highly specific pollination context. Together with observations of spatial genetic structure, these findings suggest a shift in plant‐pollinator interactions within the species across different regions.