Insect pollination in temperate sedges? A case study in <i>Rhynchospora alba</i> (Cyperaceae)

Sedges (Cyperaceae) are commonly pollinated by wind, but some transitions from wind to insect pollination have been reported in tropical sedges. Despite being a temperate sedge, the pollination strategy of <i>Rhynchospora alba</i> may partly depend on insects, as suggested by its white-colored inflorescences. Here we quantify the contribution of insects to the reproductive fitness of <i>R. alba</i> as an exploration of the success of entomophily in temperate sedges. Honeybees and hoverflies seem to be the primary visitors of <i>R. alba</i> in the study site, and pollen of <i>R. alba</i> was recovered from the mouthparts and legs of the insects. Treatments excluding insects led to a lower reproductive fitness (regarding fruit weight and fruit viability) than those not excluding them. Therefore, insects seem to contribute significantly to the pollination of <i>R. alba</i> despite moderate morphological adaptation. We highlight the role of entomophily as an overlooked reproductive mechanism in cold-temperate sedges.