DOI: 10.5061/dryad.8nj84
title: Data from: Geographic patterns and pollination ecotypes in Claytonia virginica

description: Geographical variation in pollinators visiting a plant can produce plant
 populations adapted to local pollinator environments. We documented two
 markedly different pollinator climates for the spring ephemeral wildflower
 Claytonia virginica: in more northern populations, the pollen-specialist
 bee Andrena erigeniae dominated, but in more southern populations, A.
 erigeniae visited rarely and the bee-fly Bombylius major dominated. Plants
 in the northern populations experience faster pollen depletion than plants
 in southern populations. We also measured divergent pollen-related plant
 traits; plants in northern populations produced relatively more pollen per
 flower and anther dehiscence was more staggered than plants in southern
 populations. These plant traits might function to increase pollen
 dispersal via the different pollen vectors.
description: Pollen
 DepletionTo compare the rates of
 pollen depletion among C. virginica populations, we assessed the amount of
 pollen available in individual flowers (an estimate of the pollen standing
 crop) during the period of insect activity, from mid-morning until early
 or late afternoon. Each hour, we arbitrarily chose eight flowers scattered
 throughout the local plant population and collected the anthers from each
 flower into a microcentrifuge tube containing 1 mL of 70% ethanol. We
 chose flowers regardless of the number of dehisced anthers. We began
 anther collection each morning when the flowers’ anthers began to dehisce,
 usually between 8:45 and 10:00, but occasionally as late as 13:15 because
 of cool or wet weather. We concluded anther collection when insect
 visitation ceased or flowers began to close, between 13:00 and 15:00. We
 counted the number of pollen grains available in each flower sample using
 a Coulter Multisizer 3 particle counter (Beckman Coulter Inc., Brea,
 California). Prior to counting, we suspended pollen in 20 mL 0.9% saline.
 To obtain a representative count of the number of pollen grains in each
 flower, we took the average of four 1mL subsamples and multiplied the mean
 by the total volume of the sample. These counts included the number of
 pollen grains in undehisced anthers because undehisced anthers opened and
 emptied during the counting process.pollen
 depletion.csvAnther
 DehiscenceTo estimate the pollen
 presentation schedule in each population, we tracked anther dehiscence in
 ten male-phase flowers on each day of data collection. Prior to first
 anther dehiscence, we arbitrarily chose ten fresh male-phase flowers and
 marked them with dental floss and a label. Every 30 minutes, we recorded
 the temperature and then returned to these flowers and recorded the number
 of locules dehisced (two locules per anther for a total of ten locules).
 We concluded tracking each flower when all ten locules had dehisced or, if
 the ten locules did not dehisce completely, when insect activity
 ceased.anther
 dehiscence.csvPollen
 ProductionWe estimated total
 pollen production during each day of data collection. We covered a sample
 of male-phase flowers with fine mesh cages prior to anther dehiscence to
 prevent insect visitation. After insect visitation ended for the day, we
 collected 5-15 samples of the unvisited flowers to estimate the total
 number of pollen grains. Because we collected these flowers at the end of
 each day, these counts exclude pollen that may have passively fallen from
 anthers.pollen
 production.csvPollinator
 VisitationTo compare the
 visitation rates of flower visitors to C. virginica, we identified
 visitors to sets of flowers in sets of six 5-minute observation periods at
 each site. Observations were spread across the site, and when possible, we
 conducted 90 minutes of observations throughout the period of insect
 activity, from mid-morning until early or late afternoon. Prior to each
 observation period, we selected a new set of flowers that we could observe
 simultaneously, marked them using a hula hoop or embroidery hoop
 (depending on floral density), and recorded the number of male- and
 female-phase flowers. During the observation period, we identified each
 visitor and counted the number of visits by that visitor by to male- and
 female-phase flowers. We used knowledge from multiple years of collecting
 (Williams et al. 2013) to identify A. erigeniae to species and sex,
 Bombylius major to species, generalist bees in the genera Lasioglossum,
 Ceratina, and Hylaeus to a group we called “small generalist bees”,
 cleptoparasitic bees in the genus Nomada to genus, and other visitors to
 species, genus, or morphological group to the best of our
 abilities.visitation.csv