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Insect Pollinator Voucher Collection: Pollinator Visitation to Pacific Northwest 
Native Plants and Native Cultivars

Jen J-M. Hayes*a, Nicole C. Bella, Lincoln R. Besta, Svea R. Bruslinda, Devon O. Johnsona,  
Mallory E. Meada, Tyler S. Spofforda and Gail A. Langellottoa 

* Corresponding author: Jen.JM.Hayes@gmail.com
a Department of Horticulture, Oregon State University, Corvallis, OR 97330, USA.

  
Cite this work as: 

Hayes, Jen J-M, N.C. Bell, L.R. Best, S.R. Bruslind, D.O. Johnson, M.E. Mead, T.S. Spofford and G.A. Langellotto. 2024. 
Insect Pollinator Voucher Collection: Pollinator Visitation to Pacific Northwest Native Plants and Native 
Cultivars. Catalog. Oregon State Arthropod Collection. 8(1) p 1 —8.  
DOI: https://dx.doi.org/10.5399/osu/cat_osac.8.1.6034.

Abstract

Planting native flora continues to grow in popularity as a means of conserving pollinator fauna in fragmented 
landscapes. Due to the limited availability of native plants, consumers may encounter cultivars in their search 
for plants native to their region. Though consumers have a documented interest in planting native flora for 
their purported benefits to pollinators, it is unclear whether cultivars provide the same benefits as wild-type 
native plants. Over three years (2020-2022), we observed and collected pollinators from a common garden 
experiment in Corvallis, OR containing 8 species of Pacific Northwest native plants, 18 cultivars derived from 
native plant species, and one exotic perennial plant. Methods for collection are described in further detail 
in Hayes et al. (in prep.). Here, we report on and document the deposition of taxonomic voucher specimens 
(OSAC_AC_2024_01_30-001), which represent the primary species concepts used throughout Hayes et al. 
(in prep.). Specimens were identified to the lowest possible taxonomic level by L. R. Best (bees, Hymenoptera: 
Apoidea) and J. J-M. Hayes (syrphid flies, Diptera: Syrphidae). The vouchered material includes 139 individual 
specimens with at least one representative per caste and sex, as available, of 55 species and 14 morphospecies 
of bees (Hymenoptera: Apoidea) and 13 species and one morphospecies of syrphid flies (Diptera: Syrphidae). 
Additional vouchers are included for specimens identified only to the morphospecies level, and Megachile 
brevis Say, 1837 individuals that were captured while collecting sections of petals from Clarkia amoena (Lehm.) 
A.Nelson & J.F.Macbr. plants. These 139 voucher specimens come from a much larger dataset, containing over 
6,500 observational records of plant-pollinator interactions. 

Introduction

Planting native flora is a popular practice to conserve pollinators and other wildlife in fragmented landscapes. 
The number of nurseries that specialize exclusively on native plants, however, is limited (Oregon State University 
Survey Research Center & Langellotto, 2023; Rihn et al., 2022; White et al., 2018). Consumers looking to buy 
native plants, then, may encounter difficulties sourcing plants (Anderson, 2022, 2019; Brzuszek et al., 2010) or 
cultivars of native plants, which are not necessarily representative of wild genotypes (Coombs et al., 2020; Wilde 
et al., 2015). Research evaluating pollinator use of cultivars, compared to native plants, has yielded mixed results 
(Baisden et al., 2018; A. M. Baker et al., 2020; Dibble et al., 2020B; Nevison, 2016; Ricker et al., 2019; Torrez et 
al., 2023; White, 2016), and has yet to explore plant taxa native to the Pacific Northwest. We thus selected 8 plant 
species native to the Pacific Northwest and 18 cultivars of those native plants, to evaluate in a common garden 



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experiment. We additionally included one popular, exotic plant (lavender, Lavandula x intermedia ‘Grosso’) in 
our trial to understand the pollinator communities visiting lavender in gardens. The other goals of our project 
were to understand if pollinators differentially visit native plants and cultivars, and to identify potential plant 
traits that may drive pollinator visitation. The focal pollinator groups we explored includes bees (Hymenoptera: 
Apoidea), butterflies (Lepidoptera: Papilionoidea), and syrphid flies (Diptera: Syrphidae). 

Methods

Over three field seasons (2020-2022) we vacuum-sampled pollinators from a common garden experiment at the 
Oak Creek Center for Urban Horticulture in Corvallis, OR. Additional information about plant establishment, 
sampling protocols, and methodology can be found in Hayes et al. (in prep). Pollinators were also recorded, 
without specimen retention, in some cases. Butterflies were collected in a net for identification, and then 
immediately released. A single honey bee (Apis mellifera L.) was collected from each plant during each sample, 
but remaining individuals were counted and recorded. A single queen bumble bee (Bombus flavifrons Cresson) 
was also released in 2022 after taking photographs and adding the observation to iNaturalist (Hayes, 2022). 
The voucher material described here are based upon specimens that were collected and retained only (OSAC_
AC_2024_01_30-001).

L. R. Best identified bee specimens and J. J-M. Hayes identified syrphid fly specimens. Specimens were identified 
to the lowest taxonomic level possible, using taxonomic and identification resources listed in Table 1. At least one 
representative per caste and sex, as available, of each species and morphospecies of collected bees and syrphid 
flies were curated for deposition in the Oregon State Arthropod Collection in Corvallis, OR. Additional vouchers 
were included for taxa identified to the morphospecies level and for individuals collecting petals from Clarkia 
amoena plants. A corresponding dataset containing only the vouchered material is presented here. Current 
nomenclature and taxonomic authority for each taxon was obtained using the GBIF Species Matching Tool. 

The dataset contains 49 DarwinCore fields, including:

occurrenceID: a unique identification number and URL to the observational record of an individual specimen 
in the OSAC museum record. The observational records are not yet connected to the museum’s inventory. For 
each specimen, the prefix http://osac.oregonstate.edu/SP/OSAC_ is followed by a 10-digit museum-issued 
catalog number, e.g., 0001310208, to build the entire occurrence ID (e.g., http://osac.oregonstate.edu/SP/
OSAC_0001310208). 

catalogNumber: a unique catalog number for voucher specimens deposited into the OSAC collection. The 
catalogNumber is the last portion of specimens’ occurrenceID (e.g., OSAC_0001310208), and was also printed 
on a physical label attached to the specimen. 

fieldNumber: a unique identification number that ties a voucher specimen to a row in Hayes et al.’s entire 
database of collected specimens. The prefix (NNP) indicates specimens collected from the Native Plant and 
Native Cultivar Project, which is followed by a four-digit year of collection (2020, 2021, or 2022), and a four- or 
five-digit collection ID (e.g., 00001).

disposition: though not all specimens in our study were retained, all vouchered specimens are confirmedPresent.

datasetName: Hayes_etal_vouchers2023.csv; included with each record to identify where the records came from 
if they are ever compiled in other datasets.



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basisOfRecord: all observational records in the voucher dataset were based upon pinned specimens. 
bibliographicCitation: a full bibliographic citation was included for each record to allow individual specimens to 
be referenced and the authors to be credited for the use of records in future works.
license: specimen records were released under a creative commons license. Non-commercial use is permitted 
with proper attribution.

institutionCode: OSAC

ownerInstituionCode: OSAC

rightsHolder: Oregon State University

Collecting Date: the date of collection is included across four fields including: verbatimEventDate which is 
formatted as m/dd/yyyy (e.g., 7/11/20), year (2020, 2021, or 2022), month (1-12), and day (1-31).

Collection Locality: locality information is reported across 6 fields (country, stateProvince, county, locality, 
decimalLongitude, decimalLatitude). All specimens were collected at a single site in Corvallis, OR with 
georeferences consistent across all records.

samplingProtocol: all collected specimens were sampled using a modified RYOBI ONE+TM 18V battery-
powered hand vacuum (Bioquip Products, Gardena CA).

associatedTaxa: all records were sampled directly from plants. Here, we record all specimens as “foraging on” 
:  followed by the scientific name of the plant taxon in quotation marks. Wild-type native plants are listed with 
their scientific name (genus, specific epithet, and subspecies as appropriate) only (e.g., Clarkia amoena lindleyi), 
cultivars are identified by a name in single quotation marks (e.g., Clarkia amoena ‘Dwarf White’) following the 
genus or scientific epithet. A genus followed by a cultivar name is indicative of a hybrid plant (e.g., Nemophila 
‘Penny Black’), and plant taxa with an x between their genus and cultivar name are interspecific hybrids (e.g., 
Achillea x ‘Moonshine’).

recordedBy: the name of the person that collected an individual record.

Taxonomic Information: taxonomy is recorded across 10 fields (scientificName, phylum, class, order, family, 
genus, subgenus, specificEpithet, identificationRemarks, and rank). Scientific names, authorities, and publication 
dates were verified using the GBIF Species Name Tool. The identificationRemarks field contains morphospecies 
identifiers for records identified only to the genus level (e.g., sp. 1).

identifiedBy and dateIdentified: records were identified by L. R. Best or J. J-M. Hayes in 2023.



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Table 1. List of keys, guides, and other resources used for identification of bee and syrphid fly 
specimens.

Focal Taxa Identification Resources
Diptera: Syrphidae Churran & Fluke, 1926; Knutson, 1973; Miranda 

et al., 2013; Skevington et al., 2023; Telford, 1970; 
Vockeroth, 1958; Vockeroth & Thompson, 1993. In 
addition to:  
 
BugGuide. Identification, images, & information for 
insects, spiders, & their kin for the United States and 
Canada. Available from https://www.bugguide.net/
node/view/15740. (Used as a reference for Syrphidae 
known to exist in the Corvallis, OR area.) 

iNaturalist. Available from iNaturalist.org. (Used 
as a reference for Syrphidae known to exist in the 
Corvallis, OR area.) 

Hymenoptera: Andrenidae W. E. LaBerge, 1969, 1977; Michener, 2007a.
Hymenoptera: Apidae Brooks, 1988; CANPOLIN Bee Course, 2012; Daly, 

1973; Koch et al., 2012; W. LaBerge, 1956, 1961, 
1963; Ram, 1969; Rightmyer, 2008; Timberlake, 
1969; Williams et al., 2014.

Hymenoptera: Colletidae Oram, 2018; Snelling, 1966, 1967, 1970.
Hymenoptera: Halictidae Gardner & Gibbs, 2023; Gibbs et al., 2013; McGinley, 

1986, 2003; Roberts, 1972, 1973. In addition to:

Engler et al (In prep.). Draft key to females of 
Lasioglossum subgenera Evylaeus, Hemihalictus, and 
Sphecodogastra. 

Hymenoptera: Megachilidae J. R. Baker, 1975; Bzdyk, 2012; Hurd & Michener, 
1955; Michener, 2007b; Mitchell, 1937; Rightmyer 
et al., 2013; Rust, 1974; C. Sheffield et al., 2011; C. S. 
Sheffield, 2020.

Results

The voucher material and included dataset document 139 individual specimens, from 55 species and 14 
morphospecies of bees and 13 species and one morphospecies of syrphid flies. We included five Megachile brevis 
Say females that were sampled while they were actively cutting segments of Clarkia amoena petals from plants. 



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Discussion

The data presented here are a subset of a dataset containing over 6,500 observational records of plant-pollinator 
interactions. The vouchered specimens represent over 30 pollinator genera that vary in their life histories: from 
highly abundant eusocial species (e.g., Apis mellifera and Bombus vosnesenskii), to uncommon eusocial species 
(Bombus caliginosus), as well as several pollen-specialist taxa (Diadasia nigrifrons, Megachile apicalis, M. fidelis, 
M. gravita, Melissodes clarkiae, Me. lupinus, Me. microstictus). These specimens are currently being used to 
help understand the pollinator communities visiting native plants, native cultivars, and lavender in Oregon, and 
may have further applications for use in understanding pollinator foraging preferences as well as non-trophic 
herbivory.

Acknowledgements

Our research was conducted, and samples were collected “within the traditional homelands of the Mary’s River, 
or Ampinefu Band of Kalapuya. Following the Willamette Valley Treaty of 1855 (Kalapuya etc. Treaty), Kalapuya 
people were forcibly removed to reservations in Western Oregon. Today, living descendants of these people are a 
part of the Confederated Tribes of Grand Ronde Community of Oregon (https://www.grandronde.org) and the 
Confederated Tribes of the Siletz Indians (https://ctsi.nsn.us)” (Kaku-Ixt Mana Ina Haws, 2016 Nov 8).

Our research was supported by the Native Plant Society of Oregon, the Garden Club of America, the Oregon 
Department of Agriculture, and Y. Sherry Sheng. Our plants were sourced with support from Annie’s Annuals 
and Perennials, Bluestone Perennials, Eden Brothers, Gray’s Garden Center, Heritage Seedlings, Xera Plants, Inc., 
Northwest Meadowscapes, Seven Oaks Native Nursery, Silver Falls Seed Co., Willamette Gardens LLC, Easy to 
Grow Bulbs, and Native Foods Nursery. And we thank Angelee Calder, Isabella Messer, Jay Stiller, Cliff Brock, 
Mericos Rhodes, Elliot Ariel and Aaron Anderson in assisting with the initial phases of this research.

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