Bee specialists like to point out that the yellowjacket is a carnivore and the honey bee is a vegetarian.

They are, indeed. The yellowjacket is an aggressive predator that seeks protein-rich foods for its colony, while the honey bee--usually quite passive unless it's defending its hive--gathers nectar and pollen.

If you've ever watched a yellowjacket invade a honey bee hive or prey upon other insects--or grab a bite of chicken from your barbecue or scavenge rotting fruit--you know how aggressive it is. 

We watched a western yellowjacket, Vespula penyslvanica (as identified by Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis), forage on a cluster of red-hot pokers along a road leading to Tomales, a tiny town in Marin County.

This wasn't a "red" red-hot poker, though. It was yellow. Varieties of the Kniphofia genus (the genus was named for 18th century German physician/botanist Johann Hieronymus Kniphof) now appear in such colors as orange, coral, cream and yellow.  

Rather fitting that a yellowjacket was on a yellow red-hot poker!

We caught it in flight as it headed toward the tubular flowers and watched it grab a few tasty morsels, an unsuspecting spider or two, to carry back to the nest. (It also sips nectar for flight fuel.) When it emerged, it was dotted with pollen grains, so you could say that sometimes it's a pollinator, too. But not a significant one...

The western yellowjacket,  native to the western United States, is a major pest in Hawaii, where it was first discovered in 1977. Erin Wilson, a former postdoctoral scholar in the Louie Yang lab in the UC Davis Department of Entomology, studies this social, ground-nesting wasp. 

Wilson, who launched the vespularesearch.com website, describes it as a "vacuum cleaner" that wreaks ecological havoc among the native species in Hawaii. 

“The introduction of non-native organisms is a leading cause of imperilment of native species,” says Wilson, who has studied the western yellowjackets at two sites: the Hawaii Volcanoes National Park on the island of Hawaii and the Haleakala National Park on Maui since 2004. 

Scientists have found that the incidence of perennial or overwintering colonies is higher in Hawaii than in its native range.

Compared to annual colonies, these overwintering perennial colonies can collect twice as many prey items and produce 10 times the worker force, Wilson says. Some perennial colonies are huge, their size linked to Hawaii’s mild climate and the ability of the yellowjackets to establish perennial colonies. How huge? One Maui colony yielded 600,000 individuals. Compare that to a typical California colony of less than a few thousand wasps.

Read the PBS piece about this invasive insect in Hawaii and see it "stinging" the camera lens.

If there ever were a bug just perfect for Halloween, that would be the orange and black Harlequin cabbage bug, Murgantia histrionica, also known as a calico bug or fire bug.

Its brilliant, distinctive colors bring back memories of a circus clown. Not so surprisingly, "histrio" is Greek for clown or jester. 

We spotted this little bug foraging on cabbage in a Benicia garden. It's known as a Harlequin cabbage bug because it feeds on the juices of cabbage, kale, turnip, cauliflower, broccoli, mustard, and other cruciferous plants. You may also have seen it on such plants as beet, bean, grape, squash, potato, squash, sunflower and ragweed. 

At first glance, some folks think it's some kind of beetle, but it isn't. It's in the stink bug family, Pentatomidae. 

We imagine that the 41st President of the United States, George H. W. Bush, would gladly share his broccoli with the Harlequin cabbage bug. He's the President who publicly announced a ban on broccoli served on Air Force One and at the White House. 

"I do not like broccoli," he told the news media back in March of 1990. "And I haven't liked it since I was a little kid and my mother made me eat it. And I'm President of the United States, and I'm not going to eat any more broccoli." (U.S. News and World Report).

Score: Harlequin cabbage bug, 1. President George H. W. Bush, 0.

It's Halloween tomorrow (Wednesday) but what's really frightening is Aedes aegypti, a mosquito that transmits the deadly dengue. According to the World Health Organization (WHO), dengue is the world's most rapidly spreading mosquito-transmitted disease.

Some 2.5 billion people, or about 40 percent of the global population, are at risk from dengue, WHO says. The disease infects between 50 to 100 million people a year. The most severe form afflicts some 500,000 a year, killing an estimated 2.5 percent or 22,000.

Enter Sarjeet Gill, professor of cell biology and entomology at UC Riverside. He'll speak on on "Bacterial Toxins in Disease Mosquito Vector Control" at a seminar from 12:10 to 1 p.m., Wednesday, Oct. 31 in Room 1022 of the Life Sciences Building, UC Davis.

His longtime colleague and good friend, Bruce Hammock, distinguished professor of entomology at UC Davis, will host him as part of the UC Davis Department of Entomology's  fall seminar series. 

"Aedes aegypti is an important vector of human diseases, such as dengue fever and yellow fever," Professor Gill says. "Its control has been attempted by eliminating breeding sites, using predators and with chemical insecticides. However, such control is still difficult because of operational limitations and the development of insect resistance. Therefore, Bacillus thuringiensis has been used for decades instead of physical and chemical control methods. B. thuringiensis israelensis is highly active against Aedes aegypti."

"The high insecticidal activity and the low toxicity to other organisms," Gill says, "have resulted in the rapid use of B. thuringiensis as an alternative for the control of mosquito populations.  B. thuringiensis israelensis produces a variety of toxins that act synergistically to cause toxicity to larval populations."

Gill says his seminar "will discuss our current understanding of the mode of action of these toxins and provide evidence on how resistance to these toxins has not occurred in Aedes mosquitoes in the field even though B. thuringiensis israelensis has been used for more than three decades."

Gill’s laboratory focuses on two principal research activities. "The first area attempts to elucidate the mode of action of insecticidal toxins from the Gram positive bacteria Bacillus thuringiensis and Clostridium bifermantans," he says. "This research aims to identify novel toxins, and to gain a molecular understanding of how these toxins interact with cellular targets and thereby causing toxicity.  The second area focuses on understanding mosquito midgut and Malpighian tubules function, in particular ion and nutrient transport, and changes that occur following a blood meal."

Gill, who received his doctorate from UC Berkeley, joined the UC Riverside Department of Entomology faculty in 1983.  He helped establish the Department of Cell Biology and Neuroscience and also served as chair.  Currently he is the co-editor of the journal Insect Biochemistry and Molecular Biology.

A noted scientist and a fellow of the American Association for the Advancement of Science, Gill received his doctorate in insecticide toxicology in 1973 from UC Berkeley. See his website.

If you miss his seminar, not to worry. It's scheduled to be recorded and then posted at a later date on UCTV.  (See the index of previous Department of Entomology seminars posted on UCTV.)

Insects and Halloween just seem to go together.

What would Halloween be like without costumes depicting honey bees, ladybugs, butterflies, bumble bees, and just plain bugs?

And maybe a few termites, roaches, bed bugs and stink bugs tossed in for good measure?

The Bohart Museum of Entomology at the University of California, Davis, annually hosts two pre-Halloween open houses. One, sponsored by the Bohart Museum Society, is for donors, Entomology Department affiliates, and other invited guests. The other, hosted by the museum itself, is open to all as part of its education, teaching and public service mission.

Spiders--although not insects--are wildly popular at these functions. Spider decorations dangle from the ceiling and painted images adorn faces.

Among the most interesting "bug" costumes showing up at the Bohart last week: a monarch butterfly outfit donned by Maia Lundy of Davis Senior High School, an intern at the Bohart; and a black widow spider costume worn by Tabatha Yang, the museum's outreach and education coordinator. Tabatha and her husband, Louie Yang, assistant professor of entomology at UC Davis, are expecting their first child.

Kara Handy of Davis dressed as a witch, and a beautiful witch at that, with a stunning spider web accenting one eye. 

Another guest, carrying an insect net, creatively presented herself as a pinned specimen. (Back in 2010, graduate student Matan Shelomi dressed as Billy the Exterminator.)

The Bohart Museum, located at 1124 Academic Surge on Crocker Lane (formerly California Drive) will be open for more weekend open houses during the 2012-2013 academic year. These open houses are free and open to the public. 

The schedule includes: 
Sunday, Nov. 18, 1 to 4 p.m. Theme: "Insect Societies"
Saturday, Dec. 15, 1 to p.m. Theme: "Insects in Art"
Sunday, Jan. 13, 1 to 4 p.m. Theme: "Extreme Insects"
Saturday, Feb. 2, 1 to 4 p.m. Theme: "Biodiversity Museum Day"
Sunday, March 24, 1 to 4 p.m. Theme: "Aquatic Insects"
Saturday, April 20 (10 a.m. to 3 p.m., UC Davis Picnic Day)
Saturday, May 11, 1 to 4 p.m. Theme: "Moth-er's Day"
Sunday, June 9, 1 to 4 p.m. Theme: "How to Find Insects"

The Bohart Museum, directed by Lynn Kimsey, professor of entomology at UC Davis, houses a global collection of nearly eight million insect specimens and is the seventh largest insect collection in North America. It is also the home of the California Insect Survey, a storehouse of the insect biodiversity. Noted entomologist Richard M. Bohart (1913-2007) founded the museum in 1946.

The insect museum includes a gift shop and a live "petting zoo," complete with Madagascar hissing cockroaches, walking sticks and a rose-haired tarantula that you can hold and photograph.

The Bohart’s regular hours are from 9 a.m. to noon and from 1 to 5 p.m., Monday through Thursday.  It is closed to the public on Fridays and on major holidays. Admission is free.