DOI: 10.5061/dryad.f1vhhmgxk
title: Pollen transport networks reveal highly diverse and temporally stable plant-pollinator interactions in an Appalachian floral community

description: Floral visitation alone has been typically used to characterize
 plant-pollinator interaction networks even though it ignores differences
 in the quality of floral visits (e.g. transport of pollen) and thus may
 overestimate the number and functional importance of pollinating
 interactions. However, how network structural properties differ between
 floral visitation and pollen transport networks is not well understood.
 Furthermore, the strength and frequency of plant-pollinator interactions
 may vary across fine temporal scales (within a single season) further
 limiting our predictive understanding of the drivers and consequences of
 plant-pollinator network structure. Thus, evaluating the structure of
 pollen transport networks and how they change within a flowering season
 may help increase our predictive understanding of the ecological
 consequences of plant-pollinator network structure. Here we compare
 plant-pollinator network structure using floral visitation and pollen
 transport data and evaluate within-season variation in pollen transport
 network structure in a diverse plant-pollinator community. Our results
 show that pollen transport networks provide a more accurate representation
 of the diversity of plant-pollinator interactions in a community but that
 floral visitation and pollen transport networks do not differ in overall
 network structure. Pollen transport network structure was relatively
 stable throughout the flowering season despite changes in plan and
 pollinator species composition. Overall, our study highlights the need to
 improve our understanding of the drivers of plant-pollinator network
 structure in order to more fully understand the process that govern the
 assembly of these interactions in nature.
description: To sample the pollinator community four 1x40m transects were set
 up at the study site. Pollinators were sampled by walking each transect at
 a constant pace collecting all insects observed visiting flowers until a
 maximum of 60. Sampling took place between May and August 2019 during peak
 pollinator activity between 8:00AM and 6:00PM for 21 days across 13 weeks.
 All insects were collected with butterfly nets when they were observed
 making contact with the floral reproductive structures (anthers and
 stigma). Insect pollen loads were sampled by swabbing the body of each
 floral visitor collected with fuchsin jelly cubes. The corbiculae of bee
 species was avoided as the pollen located within it is not typically
 available for pollination. To account for ‘incidental’ pollen transport we
 only considered PT interactions where an average of five or more pollen
 grains of a specific plant species where found on a floral visitor. We
 further improved the reliability of our estimate by only removing
 interactions of ≤ 5 pollen grains that also constituted less than 5% of
 the total pollen load carried by each insect species. We evaluated PT
 network structure across early (ES), middle (MS), and late flowering
 season (LS) by constructing pollen transport networks for each individual
 week (13 total weeks) and then categorizing each week as early, middle or
 late flowering.