Posts Tagged: Robbin Thorp
Catching up with the carpenters is not always easy.
Not the construction workers--the carpenter bees.
They move fast as they buzz from flower to flower.
California is home to three carpenter bee species, says native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.
You can find Xylocopa varipuncta in the Central Valley and southern California, Arizona, New Mexico and southward through Mexico. It is large (about the size of a queen bumble bee). The females are all black, while the miles are golden/buff-colored with green eyes. The males are commonly known as "teddy bears."
X. californica is right at home in the foothills surrounding the Central Valley, the Transverse Ranges (Los Angeles) of southern California, and areas of Utah, Colorado, New Mexico and Arizona. They are large, nearly the size of X. varipuncta, but with distinctive bluish metallic reflections on their body. Females have dark smokey brown wings.
X. tabaniformis orpifex resides in most of the same areas as X. californica, but extends more into the center of the Central Valley. It is the smallest of the three species--about half the size of the other two carpenter bees. Females are all black with light smokey-colored wings. The males have light yellow hair on their face and thorax.
Carpenter bees, so named for their ability to tunnel through wood to make their nests, carve with their mandibles (jaws) but do not ingest the wood.
Thorp says he tries to convince people to learn to live with these bees as “they are important pollinators in our environment and have potential as pollinators of some crops.”
“Carpenter bees are beneficial in that they pollinate flowers in native plant communities and gardens. That far outweighs any damage to wood structures.”
“These bees are not currently managed for crop pollination,” Thorp said, “but there have been some recent studies of their potential for pollination of greenhouse tomatoes. They are good at buzz pollination and can be managed by providing suitable nest materials.”
Due to their large size, carpenter bees cannot enter tubelike blossoms such as sage, so they slit the base of corolla, a practice known as “robbing the nectar” (without pollinating the flower).
We caught up with two carpenter bees (below) robbing nectar.
Male Carpenter Bee
Female Carpenter Bee
It’s triple-digit hot and you’re relaxing in a swimming pool when suddenly you realize you have company.
A knat-sized insect with a red abdomen lands next to you. It looks like a wasp. No, it looks like a bee. Wait, what is it?
In this case (see photo below), it's a female cuckoo sweat bee from the genus Sphecodes, according to native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.
Sweat bees are attracted to perspiring skin and often drop into swimming pools where they greet you with a brief but sharp sting.
Sphecodes are cuckoo or parasitic bees. They don’t collect pollen or provide for their young because they don’t need to. They lay their eggs in the nests of other bees. When the larvae hatch, they turn villainous and eat the young of the host bee. They also steal the provisions.
These bees, from the family Halictidae, are really tiny, about 0.2 to 0.6 inches. You’ll see them from late spring until early fall
It’s a large genus, with about 80 known species in the United States and Canada, says entomologist Mace Vaughan of the Xerces Society.
In most species, females are dark red with a shiny abdomen, Vaughan says, while males have a partially or entirely black abdomen.
Call them cuckoo bees. Call them parasitic bees. Call them clepto-parasitic bees. Whatever you call them, you’ll remember that red abdomen and sharp sting.
You'll see red for just a little while.
The Smithsonian Institution is the place to "bee" on Monday, June 22.
The location: Baird Auditorium, National Museum of Natural History. The Smithsonian is located at the corner of 10th Street and Constitution Avenue NW, Washington D.C.
Thorp will discuss "Western Bumble Bees in Peril." Sydney Cameron and Jeff Lozier of the University of Illinois will examine "The Status and Trends of Midwestern and Southern Bumble Bees." Then Leif Richardson of the Vermont Department of Fish and Wildlife will cover "Bumble Bee Trends in Northeastern North America."
- Stephen Buchmann, University of Arizona, "USA Native Bee Diversity: Rarity, Threats and Conservation Ideals"
- Paul Williams, Natural History Museum, London, "A Global View of Bumble Bees and Their Conservation Status."
Michael Ruggiero of the Smithsonian Institution will moderate. He's the senior science advisor of the Smithsonian's Integrated Taxonomic System (ITIS).
Following the symposium, bumble bee experts and other scientists will continue to meet at the Smithsonian for the next two and a half days to discuss concerns about the declining bumble bee population.
The symposium is part of National Pollinator Week, which starts Monday, June 22 and continues through Sunday, June 28.
Thorp delivered a presentation on Franklin's bumble bee May 27, during one of the UC Davis Department of Entomology's noonhour sessions. Franklin's bumble bee, feared extinct or nearing extinction, is found only in one part of the world: southern Oregon and northern California. Thorp's talk was Webcast.
Thorp, a member of the California Academy of Sciences since 1986, says that the loss of a native pollinator "could strike a devasting blow to the ecosystem, economy and food supply."
Locally, we've noticed far fewer bumble bees than in past years. Last summer we spotted a few in the UC Davis Arboretum (see below). This is the yellow-faced bumble bee or Bombus vosnesenskii, the most common Califonria bumble bee.
Not so common any more.
Pollen-Packing Bumble Bee
Let's have a show of hands.
How many of you have seen Franklin's bumble bee in the wild?
Never HEARD of it, you say?
Well, you probably will never SEE it, either. Bumble bee experts think it may be extinct.
Franklin's bumble bee is native to southern Oregon and northern California, but in recent years, it's been a "no show."
"Franklin's bumble bee has the most restricted distribution range of any bumble bee in North America, and possibly the world," said UC Davis researcher Robbin Thorp, a noted authority on bumble bees. Its range is about 190 miles north to south and 70 miles east to west in a narrow stretch between southern Oregon and northern California, between the coast and the Sierra-Cascade ranges.
Its known distribution: Jackson, Douglas and Josephine counties in Oregon, and Siskiyou and Trinity counties in California. It lives at elevations ranging from 540 feet in the north to 6800 feet in the south.
Thorp launched his scientific surveys for Franklin's bumble bee in 1998. He documented about 100 of them that year. They were, he said, fairly common.
Since 2004, however, he's seen the unique bumble bee only once. And that was a solitary worker in August 2006 at Mt. Ashland, Ore.
The black-faced bumble bee (Bombus franklini) is distinguished by a black inverted U-shape on its yellow thorax. See Thorp's photo below. Note also the yellow markings atop its head.
Franklin's bumble bee frequents (or shall we say, "used to" frequent) 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 (or shall we say "used to" collect) pollen primarily from lupines and poppes and gathers nectar mainly from mints.
Thorp just returned from the region in mid-May and found nothing. He journeys to the region three to five times a year, spending several days looking for the bumble bee on each trip.
It's not there.
Thorp is concerned, as we all should be, that humankind is disturbing, destroying and altering the habitat where the native pollinators exist.
He'll be speaking on the plight of the bumble bee from 12:10 to 1 p.m., Wednesday, May 27 at 122 Briggs Hall, UC Davis. His talk will be Webcast. You can view it by signing in here at that time. Later, it will be archived on this page.
Bumble bees, Thorp said, are important to our ecosystem. Wildlife, including birds, elk, deer and bears, depend on pollination of fruits, nuts and berries for their survival.
Other species of bumble bees are commercially reared to pollinate greenhouse tomatoes, peppers and strawberries. They pollinate about 15 percent of our food crops, valued at $3 billion, Thorp estimated.
Goodbye, Franklin's Bumble Bee? Hello, distinction?
It wasn't the Battle of the Sexes.
It was the Battle of the Males.
I spotted two male carpenter bees buzzing loudly over the salvia (sage) in our back yard Saturday morning. Each was lying in wait for a female, but instead found a competitor.
Now male carpenter bees are quite territorial and these two were no exception. The would-be suitors chased one another all over the yard, from saliva to salvia. One would buzz into a blossom for a quick nectar fix and the other would aggressively chase it away.
One stopped long enough, however, for me to capture his photo.
Ol' Blue Eyes.
UC Davis entomologist-pollinator specialist Robbin Thorp, professor emeritus, identified this male as a Xylocopa tabaniformis orpifex Smith
It's the most common carpenter bee in the Davis area, Thorp said. "It loves to nest in redwood structures: fences, arbors, picnic tables, etc. It is the smallest of the three carpenter bees in California. The males are quite variable in hair color on the thorax: from virtually all dark, to some yellow in front of the wing bases, to virtually all yellow on top."
Another carpenter bee increasingly found in the Davis area is the valley carpenter bee. The sighting of the male, a green-eyed fuzzy yellow "teddy bear," prompts lots of calls to the UC Davis Department of Entomology. "What is it?" they ask.
We point them to our Web page for the scoop on the three types of carpenter bees found in California.
As spring unfolds, expect to see more of them.
Ol' Blue Eyes
Ol' Green Eyes