Cycad mutualist offers more than pollen transport

Am J Bot. 2010 May;97(5):841-5. doi: 10.3732/ajb.0900251. Epub 2010 Apr 9.


Specialist insects share obligate mutualisms with some contemporary cycad species whereby the insect's pollination services are rewarded with a nursery in which the insect's larvae consume the postdispersal male cone. I prevented visits of the pollinator moth Anatrachyntis sp. to male Cycas micronesica (Cycadaceae) cones to show that consumption of the cone tissue by the mutualist hastened initiation of the plant's subsequent reproductive event. This is the first documented case where removal of a postdispersal cycad pollination organ speeds up subsequent reproductive events, and the current paradigm that the offering of cone tissue as a nursery is a sacrifice by the plant in return for the pollination services is therefore inaccurate. In C. micronesica, the herbivory stage of pollination mutualism confers a cryptic benefit of cone tissue disposal, which translates into an increase in ultimate lifetime reproductive effort. The plant population relies on the pollinator for moving gametes, as well as for increasing the number of male coning events. The dual benefits afforded to the plant by associating with this pollinator shows that mutualism can operate simultaneously on very different traits.