Posts Tagged: Robbin Thorp
If you visit the Jepson Prairie Reserve near Vacaville-Dixon in Solano County, keep your eyes out for Andrena (mining) bees on the meadowfoam (Limnanthes).
We were out there Monday morning and saw a mining bee nestled inside a white flower cup. The bee, about the size of a grain of rice, wasn't moving.
Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis, and a noted expert on "Vernal Pool Flowers and their Specialist Pollinators," identified the bee below as a male Andrena (mining bee) and "most certainly Andrena pulvera, the species whose females specialize on Limnanthes as their pollen source."
The males have no burrows. "They spend the night inside the meadowfoam flower cups so they are frequently encountered as 'sleeping' inside them early in the morning. As soon as the sun warms them up, they go about their business searching for meadowfoam patches for females."
A short distance away, we spotted another Andrena doing the same thing.
Life is good.
Andrena bee on meadowfoam. (Photo by Kathy Keatley Garvey)
Andrena bee cradled inside a meadowfoam at the Jepson Prairie Reserve. (Photo by Kathy Keatley Garvey)
At first I thought it was a yellow-faced bumble bee.
Sort of like applying the adage, "When all you have is a hammer, everything looks like a nail." That's because most of the bumble bees I see are the yellow-faced bumble bees (Bombus vosnesenskii).
Our bumble bee guru, native pollinator specialist Robbin Thorp, emeritus professor of entomology, quickly identified it as Bombus melanopygus, commonly known as the “Black Tail” bumble bee (melano = black; pygus = tail end of the abdomen).
Thorp says it's probably a queen that "just started her nest."
"Workers at this time of year would be quite small."
The queen was nectaring on Ceanothus in the Häagen-Dazs Honey Bee Haven, a half-acre bee friendly garden at the Harry H. Laidlaw Research Center at the University of California, Davis.
She was packin' pollen
Initially, Thorp suspected that the pollen load came from the nearby almond trees. "On closer inspection, the pollen loads look more yellow, so they may be from Ceanothus, but they seem a bit darker than what the honey bees foraging on Ceanothus are carrying," he said. "This could be to the difference in nectar added by the different bees to moisten the pollen pellets."
The queen buzzed around the Ceanothus as if she were late for an appointment.
A sip of nectar and she was gone.
Black-Tail Bumble Bee
From the Top
Some species of bumble bees are disappearing at an alarming rate.
And that, in itself, is alarming.
A three-year study published Jan. 3 in the Proceedings of the National Academy of Sciences (PNAS) “uncovered major losses in the relative abundance of several bumble bee species and declines in their geographic range since record-keeping began in the late 1800s,” according to a University of Illinois press release.
The interdisciplinary study, led by Sydney Cameron of the Department of Entomology and Institute for Genomic Biology, University of Illinois, showed that "declining bumble bee populations have lower genetic diversity than bumble bee species with healthy populations and are more likely to be infected with Nosema bombi, an intracellular parasite known to afflict some species of bumble bees in Europe."
“The national analysis found that the relative abundances of four of the eight species analyzed have declined by as much as 96 percent and that their surveyed geographic ranges have shrunk by 23 to 87 percent,” according to the news release. “Some of these contractions have occurred in the last two decades.”
Cameron and his colleagues studied eight of the 50 species of bumble bees found in North America. Of the eight, four are significantly in trouble.
Said Cameron: "They could potentially recover; some of them might. But we only studied eight. This could be the tip of the iceberg.”
Noted bumble bee expert Robbin Thorp, emeritus professor of entomology at UC Davis, today discussed the declining bumble bee population with KTVU Fox 2 health and science editor John Fowler. The segment aired tonight on the 6 o'clock news.
Thorp and Fowler walked around the Häagen-Dazs Honey Bee Haven, a bee friendly garden planted next to the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road. Thorp monitors the garden for bees.
The Cameron study looked at three western bumble bees: Bombus vosnesenskii (yellow-faced bumble bee), B. bifarius, and B. occidentalis.
Of those western bumble bees, only B. occidentalis is in decline “and that one only in the western part of its range,” Thorp told us.
“Although the study treated B. pensylvanicus as the eastern species in decline, the researchers did not consider its very close western relative, B. sonorus, which used to be very common here and the rest of the Central Valley, but has virtually disappeared here since about 2003,” Thorp said.
"Both these species are doing well from the southern USA down into Mexico, however. This is a curious reversal of what one would expect if global warming might be a cause.”
Bumble bees, commercially reared to pollinate greenhouse tomatoes, peppers and strawberries, pollinate about 15 percent of our food crops, valued at $3 billion, Thorp said.
Thorp has been tracking the now critically imperiled Franklin's bumble bee (Bombus franklini) since 1998. "It has the most restricted distribution range of any bumble bee in North America and possibly the world. 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 Sierra-Cascade range,” he said.
Its known distribution includes 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.
The decline, disappearance and possible demise of Franklin’s bumble bee, is closely linked to the widespread decline of native pollinators in North America, Thorp said, and should concern all facets of society. “The loss of a native pollinator could strike a devastating blow to the ecosystem, economy and food supply.”
Yellow-Faced Bumble Bee
Then it lands and you realize it's neither.
It's a bee.
The insects buzzing in our catmint last weekend were wool-carder bees, Anthidium manicatum (Linnaeus), as identified by several UC Davis entomologists: Tom Zavortink of the Bohart Museum of Entomology; native pollinator specialist Robbin Thorp, emeritus professor of entomology, and Lynn Kimsey, director of the Bohart Museum of Entomology.
Regarding the carder bee, Zavortink teamed with Sandra Shanks, then of the Bohart Museum, to write a scientific note, "Anthidium manicatum (Linnaeus) (Hymnoptera: Megachilidae in California)," published in the July 2008 edition of the journal Pan-Pacific Entomologist.
"The Palaearctic wool-carder bee Anthidium manicatum (Linnaeus, 1758) was introduced into New York state, presumably from Europe, before 1963 (Jaycox 1967)," Zavortink and Shanks wrote. However, it wasn't detected in California until much later. In 2007, an image of a carder bee from Sunnyvale, Santa Clara County, appeared on the Bug Guide website.
The name, carder bee, comes from its behavior of gathering "down" or "fuzz" from leaves to build its nest.
"Anthidium manicatum builds a linear row of cells, each one being lined and partitioned with cottony down 'carded' from hairy leaves," wrote Christopher O'Toole and Anthony Raw in their book, Bees of the World. "The term 'carder' refers to the teasing out or carding of woollen or cotton fiber with a comblike tool. The female of A. manicatum has five sharp teeth on each jaw and these are her carding tools."
The males are very territorial, the three UC Davis entomologists agreed.
Indeed they are.
The males, about the size of honey bees, buzzed furiously around the catmint last weekend. When they spotted an "intruder," such as a honey bee, they hit it with such force (body slam!) that the victim dropped to the ground.
We also observed carding of the leaves and mating. An Indy-500 male grabbed a female foraging on a catmint blossom.
"It appears that carder bees don't mate in flight like the honey bees do," commented Extension apiculturist Eric Mussen of the UC Davis Department of Entomology faculty.
Zavortink-Shanks and O'Toole-Raw reported that carder bees prefer the downy leaves of such plants as lamb's ear (Stachys lanata).
By the looks of the activity last weekend in our bee friendly yard, it appears that carder bees are also quite fond of catmint (Nepeta) and sage (salvia).
Female carder bees
Love on a Catmint
Carpenter bees, which to the uninitiated look like bumble bees, are nice to have around the garden.
Maybe not so nice to have around your untreated patio or fences (as they drill holls in them to make their nests) but just think of them as pollinators, not pests.
As native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, says: "Carpenter bees are beneficial in that they pollinate flowers in native plant communities and gardens. That far outweighs any damage to wood structures.”
We receive many calls and emails about carpenter bees. Many folks just want to know "what that loud buzz is" or "what's sharing our garden."The other day we received an email from a carpenter bee enthusiast in Patterson who wanted to know how to keep attracting them to her garden.
She inquired: "I had a couple of female bees (Xylocopa varipuncta) visit my garden this summer, but they seemed only interested in Salvia apiana and citrus flowers. Do you have any idea of other flowers that might interest them (I would like to keep them around longer)? Prefer California native plants."
Thorp responded: "Xylocopa varipuncta is a generalist flower visitor and has been recorded from a number of different kinds of flowers. Some natives you might consider include: Asclepias, Salvia, Trichostema, and Wislizenia for nectar; Eschscholzia and Lupinus for pollen.
Asclepias? The milkweeds. Salvia? Sages. Trichostema? The culinary herbs such as basil, mint, rosemary, oregano, lavender, and thyme. Wislizenia? Think Wislizenia refracta, also called by its common name, jackass clover. Eschscholzia? California poppies. Lupinus? Lupines.
In our yard, carpenter bees are partial to a variety of native and non-native plants, including salvia, lavender, catmint, rock purslane, purple oregano and African blue basil. They also like the golden day lilies and poppies.
Piercing the Corolla
On Rock Purslane