Research on Garden Bees

At least 213 bee species have been collected from a garden. Urban areas often have more bee species than natural or agriculture areas. In urban areas, gardens promote bee abundance and diversity.

  • Gardens may filter bees: gardens have fewer andrenids (spring-foraging bees), fewer soil-nesting bees, more cavity nesting bees.
  • Urban areas filter bees: favors larger bees with increased dispersal ability, higher physiological stress tolerance, broader diet breadth, wider regional distribution.
  • Bees have thick 3 leg. Wasps have thin 3 leg. Bees and wasps have long antennae. Flies have stubby antennae. Bees have branched hairs. Flies and wasps have straight hairs. Only bees collect pollen!
  • Most gardeners are interested in pollinator conservation: 91% surveyed plant for pollinators and dedicate an estimated 515-681 acres to pollinator habitat (1,386 gardeners surveyed). Gardeners vary in their ability to identify bees and bee-friendly flowers. Oregon Bee Atlas Volunteers are the best. Master Gardeners tied for last with the general public.

Pollinator-Friendly Plants

  • Most pollinator plant lists are based upon anecdotal observations. No research-based list exists for the Pacific Northwest.
  • Our Study Plants: counted pollinators, vacuum-sampled plants for insects; 2017-2019 at field plots (1m2, separated by 6 m of turf on all sides) in Aurora, OR
Pollinator-friendly plants
Common Name Scientific Name Perennial/Annual Notes
Farewell-to-spring Clarkia amoena Annual #4 native bee D-vac (2017); #4 Bee Species Richness (2017)
Giant blue eyed Mary Collinsia grandiflora Annual  
Globe gilia Gilia capitata Annual #1 All Bees & Native Bees counts (2017); #2 All Bees counts (2018); #1 native bee D-vac (2017); #2 Bee Species Richness (2017); #5 Ranked by Gardeners
Miniature lupine Lupinus polycarpus Annual  
Common madia Madia elegans Annual #2 All Bees & Native Bees counts (2017); #3 native bee D-vac (2017); #3 Bee Species Richness (2017)
Baby blue eyes Nemophila menziesii Annual  
California Poppy Eschscholzia californica Annual #5 Native Bees counts (2017), #5 All Bees counts (2018), #1 Native Bees counts (2018), #3 Native Bee D-vac (2018); #1 Bee Species Richness (2018)
Common sunflower Helianthus annuus Annual  
Varied-leaf phacelia Phacelia heterophylla Annual #3 Native Bees counts (2018), #1 Native Bee D- vac (2018); #2 Bee Species Richness (2018)
Desert deervetch Acmispon (Lotus) parviflorus Annual  
Yarrow Achillea millefolium Perennial #2 Native Bee D-vac (2018); #5 Bee Species Richness (2018)
Pearly everlasting Anaphalis margaritacea Perennial #3 Bee Species Richness (2018)
Showy milkweed Asclepias speciosa Perennial  
Western red columbine Aquilegia formosa Perennial #1 Ranked by Gardeners
Douglas' aster Aster subspicatus Perennial #3 All Bees & Native Bees counts (2017), #2 Native Bees counts (2018); #2 native bee D-vac (2017); #1 Bee Species Richness (2017)
Common camas Camassia leichtlinii Perennial #3 Ranked by Gardeners
Oregon sunshine Eriophyllum lanatum Perennial #4 Bee Species Richness (2018)
Wild strawberry Fragaria vesca Perennial  
Oregon iris Iris tenax Perennial #2 Ranked by Gardeners
Cream Stonecrop Sedum oregonense Perennial #5 Bee Species Richness (2017)
Blue-eyed grass Sisyrinchium idahoense Perennial #4 Ranked by Gardeners
Goldenrod Solidago canadensis Perennial #4 All Bees & #5 Native Bees counts (2017); #4 Native Bee D-vac (2018)
Italian oregano 1 Origanum vulgare Perennial #1 All Bees counts (2018); #5 native bee D-vac (2017)
Catnip 1 Nepita cataria Perennial #5 All Bees Counts (2017& 2018)
Pineapple Sage 1 Salvia elegans Perennial  
Lavender 1 Lavandula intermedia Perennial #3 All Bees Counts (2018); #4 Native Bee D-vac (2018)

Garden Bees

  • Sampled 22-24 gardens around the Portland Metro area, 2017 and 2018.
  • 2017 bees have been identified
  • 36 bee species identified from 2017 samples
Garden bee species
Family Species Flight Season Native Status Floral Specificity Nesting Substrate Sociality
Andrenidae (Mining Bees) Panurginus sp. 1 ? Non-native Specialist Soil Solitary
Apidae (Cuckoo, Carpenter, Digger, Bumble, and Honey Bees) Apis mellifera Year round Native Generalist Above-ground Eusocial
Bombus calignosus 2 April - October Native Generalist Above-ground cavity Eusocial
Bombus flavifrons April - September Native Generalist Above-ground cavity Eusocial
Bombus fervidus / californicus February - October Native Generalist Above-ground cavity Eusocial
Bombus griseocollis March - November Native Generalist Above-ground cavity Eusocial
Bombus mixtus February - August Native Generalist Above-ground, above-ground cavity Eusocial
Bombus sitkensis March - September Native Generalist Above-ground cavity Eusocial
Bombus vandykei April - September Native Generalist Above-ground cavity Eusocial
Bombus vosnosenskii February - October Native Generalist Above-ground cavity Eusocial
Ceratina sp. 1 April - September Native Generalist Wood Subsocial
Ceratina sp. 2 April - September Native Generalist Wood Subsocial
Melissodes sp. 1 May - September ? Specialist Soil Social parasite
Halictidae (Sweat Bees) Agopostemon virescens April - October Native Generalist Soil Solitary
Agopostemon angelicus / texanum May - October Native Generalist Soil Solitary
Agopostemon texanum May - October Native Generalist Soil Solitary
Lasioglossum pacificum February - November Native Generalist Soil Subsocial
Lasioglossum sisymbrii January - November Native Generalist Soil Solitary
Lasioglossum titusi Year round Native Specialist Soil Solitary
Lasioglossum zonulum May - November Non-native Generalist Soil Eusocial
Lasioglossum sp. 1 ? ? Generalist Soil ?
Lasioglossum sp. 2 ? ? Generalist Soil ?
Halictus ligatus April - October Native Generalist Soil Subsocial
Halictus tripartitus April - October Native Generalist Soil Subsocial
Halictus rubicundus March -October Native Generalist Soil Subsocial
Halictus farinosus April - October Native Generalist Soil Subsocial
Sphecodes sp. ? Native Specialist Social parasite Social parasite
Megachilidae (Leafcutter and Mason Bees) Anthidium manicatum May - September Non-native Generalist Below-ground cavity Solitary
Anthidium sp. 1 Summer - Early Fall ? Generalist Below-ground cavity Solitary
Anthidium sp. 2 Summer - Early Fall ? Generalist Below-ground cavity Solitary
Megachile rotundata June - August Non-native Generalist Below-ground cavity Solitary
Megachile angelarum June - September Native Generalist Below-ground cavity Solitary
Megachile perihirta May - October Native Generalist Below-ground cavity Solitary
Megachile sp. 1 Summer - Early Fall ? Generalist Below-ground cavity, Wood, Soil Solitary
Osmia sp. 1 Spring - Fall ? Varies Below-ground cavity, Soil Solitary

Results:

  • Taxon: 3% Andrenidae; 36% Apidae; 39% Halictidae; 22% Megachilidae
  • Native Status: 89% native; 11% nonnative
  • Floral Specificity: 96% generalists; 4% specialists
  • Nesting Habit: 22% above-ground cavity nesters; 44% soil nesters; 6% social parasites; 8% wood nesters; 17% below-ground cavity nesters; 8% above-ground nesters (e.g. grass or trees)
  • Sociality: 28% Eusocial; 19% Subsocial; 36% Solitary; 6% Social Parasites

Initial impressions:

  • Sunnier, flower-rich gardens have more bees
  • Soil nesting bees were rarer than expected. More similar to NYC bees community than to other garden bee communities.
  • Ligated sweat bees, honey bees and yellow-faced bumblebees are in every garden
  • Overhead irrigation seems to depress bee abundance (and diversity)
  • If you plant it, they will come

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