Robbin Thorp (Photo by Kathy Keatley Garvey)

They're there for the pollen.

"California poppies provide only pollen--no nectar," native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, told the Pollinator Gardening Workshop last Saturday on the UC Davis campus. Thorp was one of the featured speakers at the event, sponsored by the California Center for Urban Horticulture.

Thorp, who identifies thousands of bees a year for researchers, enthralled the audience with facts about bees. Although he retired in 1994, he maintains an office at the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis, and is one of the instructors of The Bee Course.

Some of the information he presented:

• Unlike wasps, which are carnivorous, "bees are vegans." They gather pollen and nectar from plants. (They also collect water and propolis, or plant resin, for their colonies.)
• "Flowers don't have wings; so we need the pollinators to come to them."
• The global population of bees includes some 19,500 named species. Of that number, about 4000 different species of bees  occur in North America; 1600 in California, and more than 300 species of bees in Yolo County. (Over the last four years, Thorp has found more than 80 species of bees  in the Häagen-Dazs Honey Bee Haven a half-acre bee friendly garden on Bee Biology Road maintained by the UC Davis Department of Entomology and Nematology.)
• Seventy percent of bees are solitary, and most nest in the soil.
• Fifteen percent of bees are cuckoo bees; the females lay their eggs in other bees' nest and their offspring eat the provisions 
• Only 10 percent of bees are social (honey bees are among them)

Thorp recommends that if you want to attract native bees, provide food (bee plants), water and shelter.  "Leave some bare soil, avoid mulch madness, and provide bee condos (drilled blocks of wood that blue orchard bees and leafcutting bees use for their nesting sites.)

"Plant it and they will come," Thorp said. "Provide habitat and they will stay and reproduce."

Thorp is the co-author of a newly published book, "Bumble Bees of North America" (Princeton University Press) and a co-author (with Gordon Frankie of UC Berkeley and colleagues) of a pending book with the working title, "California Bees and Blooms."

One of the websites Thorp recommends is the UC Berkeley Urban Bee Lab website, http://www.helpabee.org/, which provides information on native bees, gardening for bees, and current projects and partnerships.