Maternal inheritance of mitochondrial DNA (mtDNA) was originally thought to prevent any response to selection on male phenotypic variation attributable to mtDNA, resulting in a male-biased mtDNA mutation load (‘mother’s curse’). However, the theory underpinning this claim implicitly assumes that a male’s mtDNA has no effect on the fitness of females he comes into contact with. If such ‘mitochondrially-encoded indirect genetics effects’ (mtIGEs) do in fact exist, and there is relatedness between the mitochondrial genomes...