Transitions from wind pollination to insect pollination were pivotal to the radia-tion of land plants, yet only a handful are known and the trait shifts required arepoorly understood. We tested the hypothesis that a transition to insect pollinationtook place in the ancestrally wind-pollinated sedges (Cyperaceae) and that floraltraits modified during this transition have functional significance. We paired putatively insect-pollinatedCyperus obtusiflorusandCyperussphaerocephaluswith related, co-flowering, co-occurring wind-pollinated species,and compared pairs in terms of pollination mode and functional roles of floraltraits. Experimentally excluding insects reduced seed set by 56–89% in putativelyinsect-pollinated species but not in intermingled wind-pollinated species. The pollen of putatively insect-pollinated species was less motile in a wind tunnel thanthat of wind-pollinated species. Bees, beetles and flies preferred inflorescences,and color-matched white or yellow models, of putatively insect-pollinated speciesover inflorescences, or color-matched brown models, of wind-pollinated species. Floral scents of putatively insect-pollinated species were chemically consistent withthose of other insect-pollinated plants, and attracted pollinators; wind-pollinatedspecies were unscented. These results show that a transition from wind pollination to insect pollination occurred in sedges and shed new light on the function of traits involved in this important transition.
