1. Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA
2. USDA-Agricultural Research Service, Pollinating Insects Research Unit, Logan, UT 84322, USA
3. Department of Entomology, Pennsylvania State University Fruit Research and Extension Center, Biglerville, PA 17307, USA
4. Department of Biological Sciences, Simon Fraser University, Burnaby, BC, V5A1S6 Canada
5. Department of Entomology, University of Manitoba, Winnipeg, MB R3T 2N2 Canada
6. Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
7. Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, USA
8. Department of Entomology, University of Minnesota, St. Paul, MN 55113, USA
9. Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611, USA
10. USDA Agricultural Research Service, Northern Plains Agricultural Research Laboratory, Sidney, MT 59270, USA
11. Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
12. Agriculture and Natural Resource Program, Wenatchee Valley College, Wenatchee, WA 98801, USA
13. Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
14. Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331, USA
15. Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR 72701, USA
16. Department of Ecology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
17. Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA
18. AgPollen, 14540 Claribel Road, Waterford, CA 95386, USA
19. Northwest Michigan Horticultural Research Center, Michigan State University, Traverse City, MI 49684, USA
20. National Park Service, Yosemite National Park, CA 95389, USA