Author
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Cane, James |
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Submitted to: Arthropod-Plant Interactions
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/10/2018 Publication Date: 7/23/2018 Citation: Cane, J.H. 2018. Co-dependency between a specialist Andrena bee and its death camas host, Toxicoscordion paniculatum. Arthropod-Plant Interactions. https://doi.org/10.1007/s11829-018-9626-9. DOI: https://doi.org/10.1007/s11829-018-9626-9 Interpretive Summary: Rarely are plants and their pollinating bees mutually specialized for each other. Typically, either pollen specialist bees are joined by generalists at a wildflower species, or specialized flowers are pollinated by one or more generalist bees. The bee Andrena astragali is narrowly specialized, collecting pollen solely from several species of death camas. Neurotoxic alkaloids in foliage of these plants are implicated in sheep and honey bee poisoning. In this study, two species of death camas and co-blooming wildflowers were sampled for bees at 15 sites along a 900-km-long transect across the northern Great Basin plus an altitudinal gradient in Utah’s Bear River Range. The only bee species regularly seen visiting death camas was A. astragali. In turn, this bee was never among the 170 bee species caught at 17 species of prevalent wildflowers in five states. Our field pollination experiments show that most seed production by foothills death camas results from pollinator visitation. Thus both A. astragali and some species of death camas are narrowly specialized and co-dependent for each other’s reproduction, illustrating a rare case of mutual specialization in bee:plant interactions. Technical Abstract: Among associations of plants and their pollinating bees, mutually specialized pairings are rare. Typically, either pollen specialist bees are joined by generalists in a flowering species’ pollinator guild, or specialized flowers are pollinated by one or more generalist bees. The bee Andrena astragali is narrowly specialized, collecting pollen solely from several species of death camas (Toxicoscordion). Neurotoxic alkaloids of these plants are implicated in sheep and honey bee poisoning. In this study, T. paniculatum, T. venenosus and co-blooming wildflowers were sampled for bees at 15 sites along a 900-km-long transect across the northern Great Basin plus an altitudinal gradient in Utah’s Bear River Range. The only bee species regularly seen visiting Toxicoscordion was A. astragali. In turn, this bee was never among the 170 bee species caught at 17 other species of wildflowers in five states (38,000 plants surveyed). Our field pollination experiments show that T. paniculatum is primarily an outcrosser dependent on pollinator visitation for seed set. Thus, both A. astragali and some species of Toxicoscordion are narrowly specialized and co-dependent for each other’s reproduction, illustrating a rare case of mutual specialization in bee:plant interactions. |
