Backyard Orchard News
"He is slim and intense, with graying hair and clipped sentences jagged with inflections from his years in Brazil and Japan. And he does not, perhaps cannot, quit."
So wrote freelance journalist Carrie Peyton Dahlberg, formerly with the Sacramento Bee, in her excellent profile of chemical ecologist Walter Leal, published today on the American Association for the Advancement of Science website.
Leal, professor of entomology at the University of California, Davis, "tries to understand at the molecular level exactly what an insect is smelling, and how it relies on scent to interact with the world," she wrote.
Her article included a great quote from Leal's colleague, John Hildebrand, a neurobiology professor at the University of Arizona, Tucson.
“He’s one of the most dynamic people in the field. He’s a remarkably energetic and passionate person about his work … and notorious almost for the rapid fire way he speaks. He loves to joke that he can say twice as much in a lecture as anyone else because he only says half of each word.”
It was the Leal lab that discovered the secret mode of DEET. The groundbreaking research proved that “DEET doesn’t mask the smell of the host or jam the insect’s senses," Leal said in a UC Davis Department of Entomology news story. "Mosquitoes don’t like it because it smells bad to them.”
DEET’s mode of action or how it works puzzled scientists for more than 50 years. The chemical insect repellent, developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946, is considered the "gold standard" of insect repellents worldwide. Worldwide, more than 200 million use DEET to ward off vectorborne diseases.
Scientists long surmised, incorrectly, that DEET masks the smell of the host, or jams or corrupts the insect’s senses, interfering with its ability to locate a host. Mosquitoes and other blood-feeding insects find their hosts by body heat, skin odors, carbon dioxide (breath), or visual stimuli. Females need a blood meal to develop their eggs.
In her article, Peyton Dahlberg said Leal is trying to find something better than DEET.
Wrote Peyton Dahlberg: "DEET is a flawed tool, a chemical that needs to be used at high doses, can affect human biology, and isn’t recommended for very young infants, according to Leal and others who have studied it. The point is finding something better than DEET, something more targeted to the most problematic insects and less dangerous for everything else, including people."
Leal told her that that to search for safer alternatives to DEET and other insecticides, researchers need to better understand the mechanisms of scent detection and chemical communication.
Leal indeed has a "nose for insects' sense of smell," as the AAAS headline pointed out.
They're here. They're there.
The Western yellowjacket (Vespula pensylvanica) likes to hang around bee hives.
If you're a beekeeper, you've probably seen them nesting in a rodent burrow or hollow log near your hives.
At the Harry H. Laidlaw Jr. Honey Bee Research Facility at the University of California, Davis, yellowjackets currently occupy two rodent holes a few feet from the hives. To mark the spot, beekeeper and research associate Elizabeth Frost placed a brick over each nest (see photo below).
The yellowjackets are not welcome.
Members of the Vespula genus are "the most abundant and troublesome wasps in California," according to scientists Jerry A. Powell and the late Charles L. Hogue in their book, California Insects, published by the University of California Press.
"The voracious workers attack everything in the vicinity, from resting insects to pieces of hamburgers on the picnic table," they noted, and "the colonies may become very large by late summer or fall."
Bee breeder-geneticist Susan Cobey, who divides her time between UC Davis and Washington State University, agrees that yellowjackets "can be a big problem. I've seen them kill hives."
Cobey says she's fighting them now in Island County, Washington. "I have only 10 colonies, but these are special--the imports (for bee research). The wasps are always hanging around the entrance harassing the bees."
"I've had to move hives at times because the invasion was decimating the bee population," she said. "They go for the thorax (meat). They especially like the drones being kicked out of the hives in the fall--big and juicy. This is an easy dinner so then they start going in the hives and taking workers."
One way to counter the yellowjacket invasions is to "reduce the size of the entrance so the bees can protect themselves." Also, beekeepers must "keep the hives strong and healthy--yellowjackets pick on the weak."
To decrease the yellowjacket population, beekeepers bait traps in the summer "as the reproductives come out," Cobey says.
Since yellowjackets are meat eaters and honey bees are not--you can use cat food with the bait.
"But the bait must be protected from other critters," Cobey cautions. "You can put in it an empty beehive with a very small entrance."
(Note: Postdoctoral scholar Erin Wilson of the Louie Yang lab, UC Davis Department of Entomology, will speak from 12:10 to 1 p.m., Wednesday, Dec. 1 in 122 Briggs on how yellowjackets are wreaking havoc in Hawaii. Listen live at http://uc-d.na4.acrobat.com/ucsn1/. The seminar later will be archived.)
Emerging from Hole
They probably annoy you when they invite themselves to your barbecue to partake of your hamburger and other protein-rich foods. They're persistent predators.
But, do you know that they often build their nests near bee hives? "It's one-stop shopping," says postdoctoral scholar Erin Wilson (right) of the Louie Yang lab, UC Davis Department of Entomology.
Yellowjackets prey on honey bees. They raid the hives (killing the adults and brood, and stealing honey) and take the food back to their young.
Wilson, who does research on the Western yellowjacket (Vespula pensylvanica), is the lead author of a research article published in the Nov. 11 edition of Ecology.
On Wednesday, Dec. 1, she'll discuss "Yellowjacket Life History Shifts Modify Invasion Impacts in Hawaiian Ecosystems" at a UC Davis Department of Entomology seminar, set from 12:10 to 1 p.m., in 122 Briggs Hall. The talk, open to the public, also will be webcast live at http://uc-d.na4.acrobat.com/ucsn1/ and then archived on the entomology website.
The Western yellowjacket is an introduced, invasive species in Hawaii. Native to the western United States, it was first discovered in Hawaii in 1977. It's like a "vaccuum cleaner," Wilson says, and is clearly a threat to native species in Hawaii.
“The introduction of non-native organisms is a leading cause of imperilment of native species,” says Wilson, who since 2004 has studied the social wasps at two sites: the Hawaii Volcanoes National Park on the island of Hawaii and the Haleakala National Park on Maui.
The yellowjacket “may seriously threaten endemic invertebrates that evolved in the absence of these social insects," she says. "Invasive predators affect native species directly and indirectly, and the magnitude of these effects is highly dependent on the history of the recipient community. Furthermore, the impact of this social wasp may be magnified by apparent shifts in colony structure in the introduced range."
Scientists have found that the incidence of perennial or overwintering colonies is higher in Hawaii than in the native range of V. pensylvanica.
Compared to annual colonies, overwintering perennial colonies can collect twice as many prey items and produce 10 times the worker force, Wilson says. Some perennial colonies were huge, the size linked to Hawaii’s mild climate and the ability of the yellowjackets to establish perennial colonies. One Maui colony included as many as 600,000 individuals.
Yes, that's 600,000 wasps! In its native range, the typical size is less than a few thousand wasps.
Check out Wilson's research article, yellowjacket photos and her website and then listen to her seminar on Dec. 1:
- Multiple Mechanisms Underlie Displacement of Solitary Hawaiian Hymenoptera by an Invasive Social Wasp (E. E. Wilson and D. A. Holway, Ecology journal)
- Photos from her research and UC San Diego news story
- Erin Wilson's website, Vespularesearch.com
President Obama just pardoned a couple of turkeys--Apple and Cider. They won't make it to the White House Thanksgiving dinner today.
But what he could have done--when he was pardoning the turkeys--was to praise the honey bees.
Without honey bees, Thanksgiving Day dinner--as we know it--would not exist.
It's time to "bee" thankful.
If your table includes pumpkin, cranberries, carrots, cucumbers, onions, apples, oranges, cherries, blueberries, grapefruit, persimmons, pomegranates, pears, sunflower seeds, and almonds, thank the bees for their pollination services.
Spices? Thank the bees, too. Bees visit the plants that eventually comprise our spices, including sage, basil, oregano and thyme.
Extension apiculturist Eric Mussen of the UC Davis Department of Entomology faculty, says that even milk and ice cream are linked closely to the honey bee. Cows feed on alfalfa, which is pollinated by honey bees (along with other bees).
So, pardon the turkeys? Well, at least "Apple" and "Cider." But let's praise the honey bees, too.
Bee on Pomegranate Blossom
Mark your calendar.
If you're a bee aficionada and haven't ordered your educational North American Bee Calendar, you have until Tuesday, Nov. 30 to place your order.
It's for a good cause. Proceeds benefit the pollination services work by the Xerces Society for Invertebrate Conservation and the Great Sunflower Project.
This is an order-online-only calendar, says Celeste Ets-Hokin, the Bay Area native bee enthusiast who is spearheading the second annual project. That means you won't find the calendar in any stores and you won't be able to order it after Nov. 30.
The calendar spotlights a different bee genus each month, with notes on preferred plants, nesting needs, and guidance on how to identify the genus. In other words, it's a good way to learn about bees: what they look like, where they live and how to entice them to your garden.
At the UC Davis Department of Entomology, we frequently get requests for information on bees. "What are those big black bees buzzing around my garden?" they ask. "What does a leafcutter bee look like? How can I attract bumble bees?"
If you're around entomologists, you'll hear them talking about Osmias, Lasioglossums, Xylocopas and Agapostemons.
Bees appearing in the calendar and the scientific names are:
January: Honey Bee (Apis)
February: Bumble Bee (Bombus)
March: Digger Bee (Habropoda)
April: Mason Bee (Osmia)
May: Sweat Bee (Lasioglossum)
June: Ultra Green Sweat Bee (Agapostemon)
July: Leafcutter Bee (Megachile)
August: Squash Bee (Peponapis)
September: Long-horned Bee (Melissodes)
October: Carder Bee (Anthidium)
November: Carpenter Bee (Xylocopa)
December: Cuckoo Bee (Epeolus)
The photos by Rollin Coville of Berkeley are stunning. The green metallic sweat bee glitters like emeralds.
Calendars are $15 each, which includes shipping anywhere in the United States. The international price is $18, shipping included. Orders may be placed by accessing the Xerces website or The Great Sunflower Project website.
Coville, who has a doctorate in enotomology from UC Berkeley, collaborates with Gordon Frankie of UC Berkeley and emeritus professor Robbin Thorp of UC Davis on urban bees.
Indeed, the calendar is the work of many scientists and "bee folks." Matthew Shepherd, senior conservation associate of the Xerces Society, and Ets-Hokin served as editors, and Miguel Barbosa as the graphic designer. Scientists sharing their research expertise included: Neal Williams of UC Davis; Gordon Frankie and Claire Kremen of UC Berkeley; and Rachael Winfree of Rutgers University, New Brunswick, N.J.
North American Bee Calendar