title: Insectivorous bat pollinates columnar cactus more effectively per visit than specialized nectar bat.
abstract: Plant-pollinator interactions are great model systems to investigate mutualistic relationships. We compared pollinator effectiveness between facultative and obligate nectar-feeding bats to determine how foraging specialization influences mutualistic interactions in a bat-adapted cactus. We predicted that a specialized nectarivorous bat would deliver more pollen than an opportunistic nectar-feeding bat because of specialized adaptations to nectar feeding that indicate close association with their food plants. Counter to our predictions, the opportunistic Antrozous pallidus delivered significantly more pollen grains per visit than the specialized Leptonycteris yerbabuenae. Higher pollinator effectiveness, based on visitation rates and pollen deposition levels, varied between species by site, and although A. pallidus visits flowers much less frequently than L. yerbabuenae over all sites, it is likely an effective and reliable pollinator of Pachycereus pringlei in Baja, Mexico. Our results suggest that morphological adaptations and dietary specialization on nectar do not necessarily confer advantages for pollination over less specialized plant visitors and highlight the reciprocally exploitative nature of mutualisms.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064, USA. wfrick@ucsc.edu
authors.forename: Winifred F
authors.initials: WF
authors.lastname: Frick
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Price
authors.forename: Paul A
authors.initials: PA
authors.lastname: Heady
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Kay
mesh_terms: D000818:Animals; D029421:Cactaceae / Q000502:physiology*; D002685:Chiroptera / Q000033:anatomy & histology / Q000502:physiology*; D005247:Feeding Behavior; D035264:Flowers / Q000502:physiology; D020387:Food Chain; D008800:Mexico; D057048:Plant Nectar / Q000032:analysis; D054817:Pollination; D013045:Species Specificity
chemical_list: D057048:Plant Nectar