Did pollination exist before plants?

The sexual reproduction of seed plants involves the transfer of male gametes—in pollen—to their female gametes. In flowering plants (angiosperms), this is performed with the stigma of flowers, whereas the gymnosperms (such as conifers and cycads) produce a diversity of structures on their reproductive axes to accomplish the same task. This transfer of male gametes is generally known as “pollination” and can be mediated by animals, wind, or water. Animal pollination, principally by insects, is the dominant strategy for angiosperms but also occurs in the extant gymnosperms, as well as some species of mosses. Outside of these plants, no other group of organisms has been demonstrated to interact with animals in this way, until now. On page 528 of this issue, Lavaut et al. demonstrate that a living species of red seaweed, Gracilaria gracilis, uses the isopod crustacean Idotea balthica to transfer its male gametes, substantially extending the phylogenetic scope of species that use animals as pollinators.