Bug Squad - Agriculture and Natural Resources Blogs (2024)

Finding Pollen on Echium During National Pollinator Month

• Author: Kathy Keatley Garvey

It's National Pollinator Month, and what better time to find a tiny speck of a beeon a seven-foot tower of jewels, Echiumwildpretii?

This is a sweat bee of the familyHalictidae, the second largest family of bees,comprised of some 4500 species.The family is found on every continent except Antarctica.

Sweat bees--as the name suggests--are attracted to perspiration. The oldest fossil record dates back to the Early Eocene epoch, which lasted from about 56 to 33.9 million years ago.

A tiny speck of a bee finding a tiny bit of pollen, much as it did millions of years ago...

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It's Pollinator Month: No Sweat?

• Author: Kathy Keatley Garvey

In the sweltering heat of SolanoCounty (100 degrees) during National Pollinator Month, how about an image of a sweat bee, genus Halictus, a tiny bee that's often overlooked in the world of pollinators.

It's a social bee that nests in the soil. "These nests consist of a complex of tunnels with individual brood chambers," according toCalifornia Bees and Blooms: A Guide for Gardeners and Naturalists(Heyday), the work of UC-affiliated scientists,Gordon Frankie of UC Berkeley,RobbinThorp(1933-2019) of UC Davis, and BarbaraErtterand Rollin Covilleof UC Berkeley.

My camera caught thisHalictusflying overCoreopsisin our Vacavillepollinator garden on June 5.

Camera: Nikon Z8 with a 50mm lens

Settings: Shutter speed, 1/4000 of a second; f-stop, 5; ISO500.

UC Davis distinguished professor emerita Lynn Kimsey, emeritus director of the BohartMuseum of Entomology, and BohartMuseum scientist Sandy Shanks saidthe species appears to beHalictus ligatus.

MostHalictusspecies are generalist foragers, according to the Great Sunflower Project. "They use all sorts of genera of plants from the Asteraceae to Scrophulariaceae. They are very common on composites (daisy-like disc and ray flowers) in summer and fall."

We've seen them on everything from mustard to milkweeds to catmintto rock purslane, from spring to fall. They also appear regularly on the tower of jewels (Echium wildpretii).

Not to mention the Coreopsis.

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The Water Girls

• Author: Kathy Keatley Garvey

If you're struggling with triple-digit temperatures, think about the honey bees.

They need to collect water for their colony to cool the hive so their brood can develop. And for other purposes.

Just call them "The Water Girls."

Lately the bees have taken a liking to our birdbath. The birds? They're practicing social distancing.

We remember Extension apiculturistEric Mussen(1946-2022) telling us "Like most other animals, the bodies of honey bees are mostly water. Thus, they need to drink water routinely as we do. Additionally, water (or sometimes nectar) is critical for diluting the gelatinous food secreted from the head glands of nurse bees, so that the queen, developing larvae, drones, and worker bees can swallow the food. They use water to keep the brood nest area at the proper relative humidity, especially when it gets hot and dry outside the hive. Water droplets, placed within the brood nest area, are evaporated by fanning worker bees and that cools (air conditions) the brood nest area to keep the eggs and developing brood at the critical 94 degrees Fahrenheit required for proper development."

Unlike us, honey bees cannot simply turn on a faucet. "They will fly up to nearly five miles to find a suitable watering source," Mussen told us back in 2014. "Suitable to honey bees might not be suitable to us, but if it is moist, it may be visited. Suitable to the neighbors is a separate question. Honey bees can become quite a nuisance if they visit drippy irrigation lines or hose connections, birdbaths, pet water dishes, swimming pools, fountains, or wet laundry and the like. The water foragers become habituated to those sites. If you try to dissuade the bees by drying up the source for a while, it becomes evident that the bees will visit the site every so often so they'll be around quickly after the water is returned."

What to do? "People have tried to use repellents in the water, but the bees are likely to use the odor as an attractant when attempting to relocate the water source. Some people have had success keeping bees and wasps out of their swimming pools with very lightweight oils or monomolecular films--their purpose is to prevent mosquitoes from being able to breathe. But, if the water is splashed very much, you'll require a new layer."

And all those bees struggling in your swimming pool? "Not all moribund honey bees in a swimming pool are there because they were trying to get a drink. Every day, approximately 1,000 old honey bees from each colony die naturally. This normally occurs during foraging, and the bees just flutter down to the ground, sidewalk, driveway, parking lot, or whatever they were passing over. Some flutter into swimming pools. They are not dead, yet, so they can and do inflict stings on people who bump into them on the surface of the water. "

Beekeepers should make sure there's a watering source on their property so the bees won't hunt for water elsewhere, Musssenpointed out. It should be available all year around. "Once the bees are habituated to the site, most of them will use that source."

It's also a good idea to place corks in a birdbath for the bees to stand on. Bees don't like to get their feet wet. And if they drop into the water structure, they can drown.

As for the bee tenants in our watering hole, bring 'em on.

We absolutely love "The Water Girls." The birds, well, not so much. (But they do have access to a second birdbath and a fish pond.)

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Carey Engages Audience in California's Fruit Fly Crisis

• Author: Kathy Keatley Garvey

If you missed UC Davis distinguished professor James R. Carey's well-attended seminar on "California's Fruit Fly Invasion: A 70-Year StruggleNears Critical Mass," it's now onlineon YouTube.

His seminar, which took place June 3 in Briggs Hall, UC Davis, and on Zoom, drew global interest, stretching as far as Australia.

Carey pointed out thatCallforniahas "the largest agricultural industry in the United States ($55 billion), is the fifth largest worldwide supplier of agricultural produces, grows more than 200 different crops, and "most fruit crops have been attacked by multipletephritidspecies."

The California Department of Food and Agriculture (CDFA) reported that the first Mediterranean fruit fly (medfly) outbreak occurred on June 5, 1980, he said, and as of June 3, the state has detected 18 total species of fruit flies in 350 cities, amounting to 11,000 detections.

In his hour-long seminar, Carey presented an overview of the long-developing crisis, discussed lessons learned from analysis of fruit fly detection databases, and arguedthat "in order to have any chance at stemming this ever-rising tide,CDFAand theUSDAurgently need to switch from their historic, adhoceradication strategy to a new one that is evidence-based and far more scientific."

In the closing moments, he asked "Why have oriental fruit fly outbreaks been occurring annually for the past 60 years in California?"

Because, he said, the fruit flies are "permanentlyestablished."

Carey, a 44-year member of the UC Davis faculty who is retiring in June, and a senior scholar in the Center for the Economics and Demography of Aging at UC Berkeley, researches insect biodemography, mortality dynamics, and insect invasion biology. He holds a doctorate in entomology from UC Berkeley (1980).

Carey served on theCDFA'sMedflyScientific Advisory Panel from 1987-1994, testified to the California Legislature "Committee of the Whole" in 1990 on theMedflyCrisis in California, and authored the paper "Establishment of the Mediterranean Fruit Fly in California" (1991,Science258, 457).

He is a fellow of four professional societies: Entomological Society of America, theAmerican Association for the Advancement of Science, the California Academy of Sciences, and theGerontologicalSociety of America. He is former director (2003-13) of a 11-university consortium funded by the National Institute on Aging (NIH/P01) on the evolutionary ecology of lifespan. He co-authored the book“Biodemography: An Introduction to Concepts and Methods”(Carey, J. R. and D. Roach. 2020; Princeton University Press) and authored the books, “Demography for Biologists (Oxford University Press 1993), Longevity (Princeton University Press, 2003), and Longevity Records: Life Spans of Mammals, Birds, Amphibians and Reptiles (Odense, 2000) as well as more than 250 journal articles and book chapters.

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A Bumble Bee's Beeline for a Rock Purslane

• Author: Kathy Keatley Garvey

We miss the lateRobbinThorp, 1933-2019, distinguished emeritus professor of entomology at UC Davis, who co-authoredBumble Bees of North America: an Identification Guide(Princeton University Press, 2014).

He loved to share his expertise on bumble bees, which originated more than 100 million years ago. But their distribution and diversity are not well known, he used to tell us.

Bumble bees are just one of the some 20,000 species of bees that populate the world. Of that number, however, only about 250 species are bumble bees, and they all belong to the genusBombus.

Some 46 different species of bumble bees reside in North America, north of Mexico, Thorprelated for aBug Squadblogposted on July 10, 2014.

In their book, lead author Paul Williams and co-authorsThorp, Leif Richardson and SheilaCollapublished information about bumble bees and their history, plant favorites, distribution maps, up-to-date taxonomy, and extensive keys to identify the many color patterns of the species.

They list sites to spot bumble bees:

• farms and gardens with a diversity of flowering crops and herbs
• hay fields
• roadside ditches
• windbreaks with good abundance and diversity of “weedy” flowering plants, such as clovers and vetches
• wetlands and wet meadows
• hardwood forests
• mountain meadows, and
• urban parks and gardens

The primary species found inYoloCounty, Thorprelated, are:

• Yellow-faced bumble bee, now known as theVosnesenskybumble bee,Bombusvosnesenskii
• Yellow bumble bee,Bombuscalifornicus, now known asBombusfervidus
• Black-tailed bumble bee,Bombusmelanopygus,formerly known asBombusedwardsii. This is the first to fly in the winter and spring.
• Crotch bumble bee,Bombuscrotchii, a short-tongued species
• VanDykebumble bee,Bombusvandykei,a medium long-tongued species

Lately we've been observingB.vosnesenskii,andB.fervidus, B.melanopygusin our pollinator garden inVacaville,SolanoCounty.

Currently, B.fervidusfavors the rockpurslane, Calandrina grandiflora. What a joy to see!

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