Data for: Evaluating the influences of floral traits and pollinator generalism on α and β diversity of heterospecific pollen on stigmas
Study system Heterospecific pollen receipt was studied in 59 insect-pollinated flowering plant species from 26 families (Fig. 2 and Table S1) in the serpentine seep communities at the McLaughlin Natural Reserve in California, USA (38.8582º N, 122.4093º W). We focused on three seep communities (hereafter referred to as ‘seeps’: ‘BS’, ‘RHA’, ‘TPW’) that were less than 5 km apart (for locations see Koski et al., 2015). Flowering within the three seeps is highly synchronized between April–June due to seasonal drying (Arceo-Gómez et al., 2019; Wei et al., 2021). Pollinators are a diverse set of bees, flies, butterflies, moths, ants, wasps, beetles, and hummingbirds (Koski et al., 2015; Wei et al., 2021). Style sampling and pollen identification Each week during April 21 to June 25, 2016, we collected styles from spent (wilted) flowers of each species in the three seeps. At each sampling day at a seep, we collected multiple style samples for each species. Each sample contained three styles (stigmas) from different individuals of the same species that were stored together in 70% ethanol in a 1.5-ml microcentrifuge tube. For species with very small flowers, whole flowers were collected in the field and three styles were excised in the laboratory. From the vast collection of samples, we used a stratified random subsampling to achieve 9 samples (range 4–11) per species at each of the three seeps for heterospecific pollen characterization (total of 27 samples per species). This sampling effort was sufficient to capture the γ diversity of HP deposited on stigmas for each plant species at individual seeps (i.e., similar observed vs. asymptotic HP richness; Table S1). Out of the 59 plant species, 25 species had style samples from all three seeps, whereas 18 and 16 species had samples from two seeps and one seep, respectively (Table S1). To characterize the HP communities received by stigmas for each plant species at a seep, we acetolyzed individual samples (three stigmas and their pollen grains) and counted pollen grains with the aid of a hemocytometer. Each pollen grain was identified to species based on a pollen library created from the plants in the seeps (Hayes et al., 2022). The pollen that was not identified or not distinguishable at the species level (0.6% of all pollen scored) were clustered into congener or morphospecies groups (Wei et al., 2021).