title: Corolla chirality does not contribute to directed pollen movement in Hypericum perforatum (Hypericaceae): mirror image pinwheel flowers function as radially symmetric flowers in pollination.
abstract: Corolla chirality, the pinwheel arrangement of petals within a flower, is found throughout the core eudicots. In 15 families, different chiral type flowers (i.e., right or left rotated corolla) exist on the same plant, and this condition is referred to as unfixed/enantiomorphic corolla chirality. There are no investigations on the significance of unfixed floral chirality on directed pollen movement even though analogous mirror image floral designs, for example, enantiostyly, has evolved in response to selection to direct pollinator and pollen movement. Here, we examine the role of corolla chirality on directing pollen transfer, pollinator behavior, and its potential influence on disassortative mating. We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum perforatum. In addition, we quantified the number of right and left rotated flowers at the individual level. Pollinators were indifferent to corolla chirality resulting in no difference in pollen deposition between right and left flowers. Corolla chirality had no effect on pollinator and pollen movement between and within chiral morphs. Unlike other mirror image floral designs, corolla chirality appears to play no role in promoting disassortative mating in this species.
authors.affiliation: Department of Biology University of Maryland College Park Maryland 20742.
authors.forename: Carolina
authors.initials: C
authors.lastname: Diller
authors.affiliation: Department of Biology and Microbiology South Dakota State University Brookings South Dakota 57007.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Fenster
keywords: Disassortative mating; enantiomorphic contort aestivation; floral symmetry; mirror image; pollination; rotational symmetry