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Native pollinator specialist is the recipient of a 2010-11 Edward A Dickson Emeriti Professorship Award. Here he's shown with a photo he took of the critically imperiled Franklin's bumble bee. (Photo by Kathy Keatley Garvey) |
DAVIS---Native pollinator specialist Robbin Thorp, who has been monitoring the elusive Franklin’s bumble bee since 1998, is the recipient of a 2010-11 Edward A. Dickson Emeriti Professorship Award, University of California, Davis, to support his research on the critically imperiled bumble bee.
Thorp, a UC Davis emeritus professor of entomology, retired in 1994 but continues his research on native pollinators and pollinator decline. He is a noted expert on bumble bees.
The award memorializes a University of California regent who served longer than any other regent, from 1913 to 1946. In 1955, Dickson bequeathed an endowment to support and maintain special annual professorships to be awarded to retired academic senate faculty members.
| Two other projects received Dickson Professorship Awards at UC Davis. The others: Karen Reiser, "Diagnosis of Skin Cancer Using Harmonic Generation Imaging: Ancilliary Data"; and Robert Derlet and Charles Goodman, "Analysis of Microbial and Planktonic Communities in Small Sierra Nevada Lakes and Streams" |
Thorp researches the declining population of Franklin’s bumble bee, Bombus franklini (Frison), found only in a narrow range of southern Oregon and northern California. Its range, a 13,300-square-mile area confined to Siskiyou and Trinity counties in California; and Jackson, Douglas and Josephine counties in Oregon, is thought to be the smallest of any other bumble bee in North America and the world.
Named in 1921 for Henry J. Franklin, who monographed the bumble bees of North and South America in 1912-13, Franklin’s bumble bee frequents California poppies, lupines, vetch, wild roses, blackberries, clover, sweet peas, horsemint and mountain penny royal during its flight season, from mid-May through September. It collects pollen primarily from lupines and poppies and gathers nectar mainly from mints.
Thorp’s surveys, conducted since 1998 clearly show the declining population. Sightings decreased from 94 in 1998 to 20 in 1999 to 9 in 2000 to one in 2001. Sightings increased slightly to 20 in 2002, but dropped to three in 2003. Thorp saw none in 2004 and 2005; one in 2006; and none since.
Thorp hypothesizes that the decline of the subgenus Bombus (including B. franklini and its closely related B. occidentalis, and two eastern species B. affinis and B. terricola) is linked to an exotic disease (or diseases) associated with the trafficking of commercially produced bumble bees for pollination of greenhouse tomatoes.
Collaborators at the University of Illinois are testing that hypothesis. Since 2005, Thorp has collected numerous samples of bumble bees in Oregon, California and Arizona in cooperation with this study.
Thorp said he hopes that Franklin’s bumble bee will show the same signs of recovery as B. occidentais. In 2008, he found B. occidentalis on Mt. Ashland and in 2009, spotted it at both Mt. Ashland and Grizzly Peak. “This suggests the recovery of this species within the historic range of Franklin’s bumble bee,” he said.
On June 23, The Xerces Society for Invertebrate Conservation and Thorp petitioned the the U.S. Fish and Wildlife Service to provide an emergency listing of Franklin’s bumble bee under the National Endangered Species Act. The decision may take six months or more.
The objectives of Thorp’s research, funded by the Dickson grant, are to:
- Collect bumble bees for disease studies at the University of Illinois with emphasis on B. franklini (where and when appropriate so as not to hinder population recovery) and B. occidentalis and potential reservoir species known to co-occur with them, all within the historic range of B. franklini.
- Survey for B. franklini and B. occidentalis with emphasis on B. franklini historical sites.
- Include observations on population abundance of other species of bumble bees at monitoring sites for comparison with the two target species.
- Monitor floral visitation and track any individuals of B. franklini and/or B. occidentalis to determine their foraging behavior, subset of overall habitat used, nest site locations, and acceptance of trap-nest boxes.
Thorp, a fellow of the California Academy of Sciences, teaches “The Bee Course” every summer for the American Museum of Natural History of New York at its field station in Arizona. He chairs the Advisory Committee for the Jepson Prairie Reserve, a vernal pool ecosystem located near Dixon, and is the newly elected president of the Davis Botanical Society.
Species of the Day
(Oct. 21. 2010)
Franklin’s bumble bee, a critically imperiled bee researched by native pollinator specialist Robbin Thorp, emeritus professor of the UC Davis Department of Entomology, has been named “Species of the Day” by the International Union for Conservation of Nature (IUCN), the world’s oldest and largest global environmental network.
Headquartered in Gland, Switzerland, near Geneva, IUCN is comprised of more than 1000 government and non-governmental organizations and nearly 11,000 volunteer scientists in more than 160 countries.
Bombus franklini is on the IUCN “Red List of Threatened Species” and is classified as “critically endangered.”
The IUCN statement says in part:
“Populations of Franklin’s Bumble Bee have declined rapidly since 1998, and this species is in imminent danger of extinction. Surveys carried out over more than a decade have illustrated how quickly this bumble bee has disappeared. In 1998, 94 individuals were found at eight sites, whereas in the past four years, only one individual has been observed during surveys.
“Threats to this species include: exotic diseases, introduced via trafficking in commercial bumble bees for greenhouse pollination of tomatoes; habitat loss due to destruction, degradation and land conversion; and pesticides and pollution.”
IUCN is gathering Oct. 18-29 for the 10th meeting of the Conference of the Parties to the Convention on Biological Diversity in Nagoya, Japan, to agree on how to tackle biodiversity loss. |
Related links:
Mission to Save Franklin's bumble bee
Endangered Species Act
California’s list of endangered species
Native bees are a rich natural resource in urban California gardens (California Agriculture)
Vernal pool flowers and their specialist bee pollinators (California Vernal Pools)
Bumble bees in decline (Xerces Society)
Bumble bees in California (UC Berkeley)
Urban bee gardens (UC Berkeley)
Curriculum vitae
More (Watch his Webinar on bumble bees)
--Kathy Keatley Garvey
Communications specialist
UC Davis Department of Entomology
(530) 754-6894
