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.
Transition from wind pollination to insect pollination in sedges: Experimental evidence and functional traits
Year: 2011
