Posts Tagged: Robbin Thorp
The warmth of the sun and the lure of nectar beckoned the hover flies or flower flies to our bee friendly garden.
We saw this one nectaring the rock purslane (Calandrinia grandiflora) last weekend. Native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, identified it as "family Syrphidae, probably the genus Platycheirus."
It stood quite still, sipping the nectar and soon honey bees and a mason wasp joined it.
But for a minute, it seemed to have a "Mine" sign slapped on the blossom.
Hover fly on rock purslane
Ready for Take-Off
This uniquely colored bee is just one of some 1600 native bee species in California.
It's about one-fourth the size of a honey bee and it's difficult to photograph because (1) it's tiny and (2) it moves fast.
Gordon Frankie, professor in the Department of Environmental Science, Policy and Management, UC Berkeley, and Robbin Thorp, emeritus professor of entomology at UC Davis, and their colleagues wrote an excellent article on native bees being a rich natural resource in urban California gardens, published in the current edition of the California Agriculture journal.
You'll also want to see the video on the home page about attracting native bees to your garden.
We photographed this male Agapostemon texanus at the Mostly Natives Nursery in Tomales.
It vanished within seconds.
Green Metallic Sweat Bee
It's time to pop open a bottle of champagne and do a happy dance.
Finally, finally, we saw a yellow-faced bumble bee (Bombus vosnesenskii) in our yard.
After a 20-year absence.
Dusted with yellow pollen, it (or rather he) was nectaring the rock purslane--he, along with assorted honey bees and hover flies.
This Bombus brought to mind the May 27th Webinar that bumble bee expert Robbin Thorp, emeritus professor of entomology at UC Davis presented on "The Plight of the Bumble Bees" at UC Davis.
At the Webinar, he focused on Franklin's bumble bee (range of southern Oregon and northern California) and now feared extinct.
Thorp, a fellow of the California Academy of Sciences since 1986, is a noted authority on bumble bees. In June he served as a key speaker at a public symposium on "The Plight of the Bumble Bees" at the Smithsonian Institution, Washington, D.C. His topic: "Western Bumble Bees in Peril."
Bumble bees need our protection.
As Thorp says: "“The loss of a native pollinator could strike a devastating blow to the ecosystem, economy and food supply."
Yellow-faced Bumble Bee
Cover with Pollen
It's smaller than a honey bee.
And faster and louder.
Anthophora urbana, a solitary, ground-nesting bee, frequents our garden to nectar the catmint, lavender and sage.
Sometimes the forager's buzz is so loud that it's startling. "What was THAT?"
In this case, THAT is a female Anthophora urbana, as identified by UC Davis pollinator expert Robbin Thorp, emertus professor of entomology.
It belongs to the family Apidae, as do honey bees, carpenter bees, cuckoo bees and others. In sheer numbers, it's one of the largest in the Apidae family--more than 450 species worldwide in 14 different subgenera.
It may be tiny, but its buzz isn't.
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