title: Hawkmoth pollinators decrease seed set of a low-nectar Petunia axillaris line through reduced probing time.
abstract: Although deception of floral pollinators is well known among orchids, the majority of animal-pollinated plants secure pollination by nectar rewards. The costs and benefits of nectar production remain poorly understood. Here, we developed a crossing design to introgress a low-nectar-volume locus of Petunia integrifolia into the genetic background of P. axillaris. The resulting introgression line resembled P. axillaris but produced only one-third of the nectar volume. When exposed simultaneously to low-nectar and wild-type P. axillaris plants, hawkmoth pollinators reduced their probing duration on low-nectar plants but otherwise did not show any signs of discrimination against these plants. However, reduced probing duration resulted in reduced seed production in the low-nectar plants despite their higher reproductive potential as evidenced by hand pollination. In line with this interpretation, we found a positive correlation between probing duration and seed set, and hawkmoth pollination of low-nectar plants that were manually supplemented with nectar to parental levels yielded seed sets similar to hand pollination. Thus, a simple self-serving pollinator behavior--the adjustment of probing time in response to nectar volume--may select against reducing nectar and protect many plant-pollinator mutualisms against a drift toward parasitism.
authors: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland. anna.brandenburg@unine.ch
authors: Anna
authors: A
authors: Brandenburg
authors: Cris
authors: C
authors: Kuhlemeier
authors: Redouan
authors: R
authors: Bshary
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005247:Feeding Behavior; D018402:Manduca / Q000502:physiology*; D032306:Petunia / Q000378:metabolism / Q000502:physiology*; D057048:Plant Nectar / Q000096:biosynthesis*; D054817:Pollination; D012639:Seeds / Q000254:growth & development*; D013997:Time Factors
chemical_list: D057048:Plant Nectar