Allison, T. M.; Harrison, S. A.; Lane, N.; Camus, M. F.

Sexual signals are thought to reflect metabolic capacity, allowing females to assess male genetic quality. In insects, cuticular hydrocarbons (CHCs) are central to mate recognition and sexual signalling, and their biosynthesis is directly tied to mitochondrial metabolism. Because mitochondrial performance requires coordination between the mitochondrial and nuclear genomes, non-compatible genomes may disrupt CHC production and reduce male attractiveness. We tested this prediction using a global Drosophila melanogaster mitonuclear panel comprising 80 cybrid genotypes. Multivariate analyses of male CHC profiles revealed strong nuclear effects, smaller but significant mitochondrial effects, and substantial non-additive mitonuclear interactions that accounted for ~10% of the variance after controlling for body mass. These interactions reorganised CHC blends in genotype-specific ways, with certain hydrocarbons contributing disproportionately to differentiation. In behavioural assays, females preferentially mated with males whose mitonuclear genomes were coadapted. Conversely, coadapted males had higher copulation success than males presenting disrupted combinations to the female. Our results demonstrate that mitonuclear compatibility influences the production of sexual signals and shapes reproductive outcomes, linking genomic interactions to mate choice.