Since its discovery about a decade ago, the remarkable obligate nursery pollination mutualism between Phyllantheae plants and their pollinating seed parasites of the moth genus Epicephala has received considerable attention. Epicephala moths actively pollinate their host plants and their larvae subsequently feed on a subset of the developing seeds, leaving some seeds intact to the benefit of the plant. This plant-insect association is extremely species-specific, and each Epicephala species is locally specialised on a single host plant species. I have, together with colleagues in Japan, studied the chemical ecology of this mutualism. We have investigated odour-based host attraction and preference in the nocturnally active moths, as well as macro-evolutionary patterns of floral scent production in the monoecious plants. Our data suggest that (i) the moths have evolved strong olfactory preference for the floral scent of their host plants, and (ii) imposed strong selection on the plants to emit divergent scent signals from male and female flowers to facilitate pollination by the seed parasites.