title: Euglossine bees mediate only limited long-distance gene flow in a tropical vine.
abstract: Euglossine bees (Apidae: Euglossini) have long been hypothesized to act as long-distance pollinators of many low-density tropical plants. We tested this hypothesis by the analysis of gene flow and genetic structure within and among populations of the euglossine bee-pollinated vine Dalechampia scandens. Using microsatellite markers, we assessed historical gene flow by the quantification of regional-scale genetic structure and isolation by distance among 18 populations, and contemporary gene flow by the estimation of recent migration rates among populations. To assess bee-mediated pollen dispersal on a smaller scale, we conducted paternity analyses within a focal population, and quantified within-population spatial genetic structure in four populations. Gene flow was limited to certain nearby populations within continuous forest blocks, whereas drift appeared to dominate on larger scales. Limited long-distance gene flow was supported by within-population patterns; gene flow was biased towards nearby plants, and significant small-scale spatial genetic structure was detected within populations. These findings suggest that, although female euglossine bees might be effective at moving pollen within populations, and perhaps within forest blocks, their contribution to gene flow on the regional scale seems too limited to counteract genetic drift in patchily distributed tropical plants. Among-population gene flow might have been reduced following habitat fragmentation.
authors.affiliation: Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
authors.forename: Øystein H
authors.initials: ØH
authors.lastname: Opedal
authors.affiliation: School of Biology and Center of Excellence in Phylogeny of Living Organisms, University of Tehran, 14155-6455, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Falahati-Anbaran
authors.affiliation: Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
authors.forename: Elena
authors.initials: E
authors.lastname: Albertsen
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.|School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK.|Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA.
authors.forename: W Scott
authors.initials: WS
authors.lastname: Armbruster
authors.affiliation: School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK.
authors.forename: Rocío
authors.initials: R
authors.lastname: Pérez-Barrales
authors.affiliation: Department of Natural History, NTNU University Museum, 7491, Trondheim, Norway.
authors.forename: Hans K
authors.initials: HK
authors.lastname: Stenøien
authors.affiliation: Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
authors.forename: Christophe
authors.initials: C
authors.lastname: Pélabon
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D019665:Euphorbiaceae / Q000235:genetics*; D005260:Female; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D056626:Inflorescence / Q000502:physiology; D018895:Microsatellite Repeats / Q000235:genetics; D054817:Pollination; D014329:Tropical Climate
keywords: 
  Dalechampia
  ; Euglossini; orchid bees; paternity analysis; plant-pollinator interactions; spatial genetic structure