Sterile flowers promote female reproductive success

Large floral displays attract pollinators but can also promote among-flower self-pollination (geitonogamy). Morales et al. assess the effects of the presence of sterile flowers and fertile-flower display size in Leopoldia comosa, a spring-flowering Mediterranean geophyte. They find that the presence of bright-coloured sterile flowers at the top of the inflorescence promotes female reproductive success by increasing long-distance pollinator attraction and visitation to fertile flowers, without the need to expose many fertile flowers simultaneously. Sterile flowers thus improve pollination quality by promoting pollen export and import, while limiting the mating costs of geitonogamy associated with large fertile displays.